Probability of Oil Spills from Tankers in Canadian Waters
by
SL Ross Environmental Research Ltd.
Ottawa, Ontario
for
Canadian Coast Guard
Ottawa, Ontario
December 17, 1999
Executive Summary
The study predicts the frequency of oil spills from tankers in various regions and areas of Canada. The
expected spill rates (spills per year) are calculated by multiplying (1) the tonnage of oil loaded and
unloaded at Canadian ports by (2) spill frequencies (spills per tonnes moved) derived from historical
statistics.
Oil Traffic in Canada
Oil shipments by vessel are recorded by Statistics Canada. A summary of oil movements broken down by
Canadian Coast Guard (CCG) region is shown in Table S1. The total amount of oil loaded and unloaded
in Canadian ports in 1998 was about 72 million tonnes compared to 65 million tonnes five years ago. The
ten-percent increase is primarily due to new movements of crude oil to the major transshipment terminals
on the east coast, one at Whiffen Head in Placentia Bay, Newfoundland, to handle Hibernia oil, and one
at Port Hawkesbury to handle increasing amounts of foreign oil transshipped to ports in the northeast of
the U.S.
Saint John, handling 16 millions tonnes of oil per year, remains the largest port by far in terms of oil
movements. Tankers of size 200,000 DWT and larger bring in crude oil from various foreign sources, and
tankers of all sizes move product oil in and out of the port. This area, including the lower Bay of Fundy
which the tankers must transit to reach Saint John, is the busiest area in Canada for oil tanker traffic.
Calculating Spill Frequencies from Historical Statistics
Six spill size categories are selected for analysis, as listed below.
Exceptionally Large spills:
Extremely Large spills:
Very Large spills
Large spills:
Medium spills:
Small spills:
>200,000 bbl
>100,000 bbl
>10,000 bbl
>1000 bbl
50 - 999 bbl
1 - 49 bbl
(>27,800 tonnes)
(>13,900 tonnes)
(>1390 tonnes)
(>139 tonnes)
(6.9 - 138.9 tonnes)
(0.14 - 6.89 tonnes)
Note that the top four categories are cumulative; for example, the large-spill category (>1000 bbl) includes
the very large, extremely large and exceptionally large spills.
Spill frequencies in terms of spills per billion barrels of oil moved have been calculated on the basis of
worldwide spill and shipping statistics (for crude oil) and Canadian statistics (for petroleum products such
as gasoline, diesel oil, heavy fuel oil, etc.). A summary of these is presented in Table S2.
Executive Summary--Tanker Oil Spill Probabilities in Canada
Page 1 of 5
Table S1. Tonnage of Petroleum Loaded and Unloaded at Canadian Ports in 1998
CCG Region
Pacific
Loaded
Unloaded
Pacific Total
Central (Arctic)
Crude Oil
Tonnes
Product Oils
Tonnes
Grand Total
Tonnes
1,048,459
19
1,048,478
1,128,001.00
1,521,466
2,649,467
156,557
323,171
479,728
2,347,683
1,997,394
4,345,077
3,239,786
4,907,666
8,147,452
8,296,053
4,065,711
12,361,764
3,277,058
1,681,731
4,958,789
32,942,277
2,176,460
1,521,485
3,697,945
156,557
323,171
479,728
2,347,683
2,001,615
4,349,298
3,240,374
12,087,692
15,328,066
14,103,688
22,232,778
36,336,466
6,812,789
5,316,000
12,128,789
72,320,292
Loaded
Unloaded
Central (Arctic) Total
Central (Ont)
Loaded
Unloaded
Central (Ont) Total
Laurentian
Loaded
Unloaded
Laurentian Total
Maritimes
Loaded
Unloaded
Maritimes Total
a
Newfoundland
Loaded
Unloaded
Newfoundland Total
Grand Total
4,221
4,221
588
7,180,026
7,180,614
5,807,635
18,167,067
23,974,702
3,535,731
3,634,269
7,170,000
39,378,015
a.1999 estimate for Grand Bank/Whiffen Head
Executive Summary--Tanker Oil Spill Probabilities in Canada
Page 2 of 5
Table S2. Spill Frequencies (Inbound or Outbound Journeys) and Average and Mean Spill Sizes for Six Categories
Crude Oil Spills
Spill Category
Spill Frequencyb
Product Oil Spills
Spill Size
Spill Frequencyb
Spill Size
spills/ 109 bbl
loaded or
unloaded
spills/109 T
loaded or
unloaded
Average
Median
spills/ 109 bbl
loaded or
unloaded
spills/109 T
loaded or
unloaded
Average
Median
Exceptionally
Large, >200,000
bbl (>27,800 T)
0.050a
0.36
539,000 bbl
(74,900 T)
382,000 bbl
(53,000 T)
0
0
0
0
Extremely Large,
>100,000 bbl
(>13,900 T)
0.155
1.12
374,000 bbl
(51,900 T)
244,000 bbl
(33,800 T)
0.083
0.594
108,000
bbl
(15,000
T)
108,000
bbl
(15,000
T)
Very Large,
>10,000 bbl
(>1390 T)
0.36
2.59
183,000 bbl
(25,5000 T)
73,300 bbl
(10,200 T)
0.167
1.20
79,000
bbl
(11,000
T)
79,000
bbl
(11,000
T)
Large, >1000 bbl
(>139 T)
0.65
4.68
104,000 bbl
(14,500 T)
15,000 bbl
(2100 T)
2.5
18
6320 bbl
(878 T)
1688 bbl
(234 T)
Medium, 50-999
bbl (6.9-138.9 T)
1.5
10.8
233 bbl
(32 T)
132 bbl
(18 T)
12.3
88.6
216 bbl
(30 T)
124 bbl
(17 T)
Small, 1-49 bbl
(0.14-6.89 T)
7.8
56.2
10.4 bbl
(1.4 T)
5 bbl
(0.7 T)
36
260
10.3 bbl
(1.4 T)
5.8 bbl
(0.8 T)
a. Numbers kept at three significant digits for calculation purposes
b. These values are half the spill frequencies normalized by volumes moved because a movement includes a loading and an unloading.
Executive Summary--Tanker Oil Spill Probabilities in Canada
Page 3 of 5
Predicting Spill Rates for Tankers in Canada
The frequency numbers in Table S2 are combined with the shipping statistics in Table S1 to produce
statistics on the number of spills per year that are likely to happen in each CCG region for the six
categories of spill size range. The results are shown in Table S3. Not included in the table is the spill risk
for the movement of crude oil into Puget Sound just south of Vancouver Island. The volume of oil moved
is about 25 million tonnes per year. The estimated annual spill rate of large spills (>1000 bbl) was
calculated to be 0.061 spills per year (one such spill every 16 years).
The following conclusions can be made about the risk of oil spills across the country.
1.
The Maritimes region by far has the greatest risk of spills. Half of the expected spills in the country
are in this region. The risk picture is even worse than it seems from Table S3 because tankers with
deliveries of crude oil to Quebec must first transit and put at risk the Maritimes Region. It is not
surprising that the two largest oil spills in Canadian history, the Arrow spill in 1970 (about 15,000
tonnes) and the Kurdistan spill in 1979 (about 7,000 tonnes) occurred in this region.
2.
The Newfoundland region would be ranked number two even though ports in the Laurentian
Region load and unload more oil. The reason is twofold. First, the volume of oil moved in the
region is relatively large and is growing quickly as the oil industry produces more Grand Bank oil
and moves it by tanker to Whiffen Head through Placentia Bay. Second, much traffic to the Quebec
and Maritime ports must pass relatively close to the coast of Newfoundland, and recent experiences
with oiled birds washing ashore from illegal dumps from some of this traffic show that the
prevailing currents and winds can indeed push a large spill to the south coast of the province.
3.
Quebec would be next for obvious reasons: a substantial amount of oil is moved in the province,
the second largest amount in the country. The region is also troubled by having to deal with spills
in the St. Lawrence River. Spills in rivers are always more difficult to control than spills in low
current situations, and spills in rivers can be forced ashore quickly by winds, and smear long
stretches of coastline.
4.
For the same reason the St. Clair River in Ontario is a hot spot because a substantial amount of oil
is moved in the river, to and from Sarnia (1.5 million tonnes loaded and unloaded in 1998), and the
river has very high currents, making spill control very difficult.
5.
The Pacific region would have about double the risk of the Central region, and even more because
of the U.S. traffic to Puget Sound.
6.
The chance of a large spill (>1000 bbl) for the country as a whole is about one per year. The
average large-spill size is in the 10,000 tonne range and the median spill size is in the 2000 tonne
range. The spill of particular interest to the Coast Guard is likely to be the very large spill (>10,000
bbl) because this spill size range produces a median spill size of about 10,000 tonnes. This has been
the size of interest for planning purposes in Canada ever since the Brander-Smith panel exercise
10 years ago, and is the average spill size of the two largest spills already experienced by Canada.
This spill size has a probability of occurrence of approximately one in seven years.
Executive Summary--Tanker Oil Spill Probabilities in Canada
Page 4 of 5
Table S3. Number of Spills per Year for Canadian Coast Guard Regions
Volume
6
(10 tonnes)
crude
product
CCG Region
Number of Spills per Year
Size Range
Size Range
Size Range
Size Range
> 1,000 bbl
> 10,000 bbl > 100,000 bbl > 200,000 bbl
4.680E-03
2.592E-03
1.116E-03
3.600E-04
1.800E-02
1.20E-03
5.976E-04
0.00E+00
Size Range
1 - 49 bbl
5.616E-02
2.592E-01
Size Range
50 - 999 bbl
1.080E-02
8.856E-02
1.048
2.649
3.698
0.059
0.687
0.746
0.0113
0.2346
0.2460
0.0049
0.0477
0.0526
2.72E-03
3.19E-03
0.0059
1.17E-03
1.58E-03
0.0028
3.77E-04
0.00E+00
0.0004
0.000
0.480
0.480
0.000
0.124
0.124
0.0000
0.0425
0.042
0.0000
0.0022
0.002
0.00E+00
5.77E-04
5.77E-04
0.00E+00
2.87E-04
2.87E-04
0.00E+00
0.00E+00
0.00E+00
0.004
4.345
4.349
0.000
1.126
1.126
0.0000
0.3848
0.3848
0.0000
0.0782
0.0782
1.09E-05
5.22E-03
5.24E-03
4.71E-06
2.60E-03
2.60E-03
1.52E-06
0.00E+00
1.52E-06
7.181
8.147
15.328
0.403
2.112
2.515
0.0776
0.7215
0.7991
0.0336
0.1467
0.1803
1.86E-02
9.80E-03
2.84E-02
8.01E-03
4.87E-03
1.29E-02
2.88E-06
0.00E+00
2.88E-06
Pacific
Crude Oils
Product Oils
Pacific Total
Central (Arctic)
Crude Oils
Product Oils
Central (Arctic) Total
Central (Ont)
Crude Oils
Product Oils
Central (Ont) Total
Laurentian
Crude Oils
Product Oils
Laurentian Total
Maritimes
Crude Oils
Product Oils
Maritimes Total
Newfoundland
Crude Oils
Product Oils
Newfoundland Total
23.975
12.362
36.336
1.346
3.204
4.551
0.2589
1.0948
1.3537
0.1122
0.2225
0.3347
6.21E-02
1.49E-02
7.70E-02
2.68E-02
7.39E-03
3.41E-02
8.63E-03
0.00E+00
8.63E-03
7.170
4.959
12.129
0.403
1.285
1.688
0.0774
0.4392
0.5166
0.0336
0.0893
0.1228
1.86E-02
5.96E-03
2.455E-02
8.00E-03
2.96E-03
1.097E-02
2.58E-03
0.00E+00
2.581E-03
Total for Canada
72.320
10.750
11 per year
3.343
3 per year
0.771
0.142
0.064
0.012
one per year one in 7 years one in 16 years one in 86 years
Median Spill Size
<0 .5 Tonnes
< 2 Tonnes
2100 Tonnes 10,200 Tonnes 33,800 Tonnes 53,000 Tonnes
Executive Summary--Tanker Oil Spill Probabilities in Canada
Page 5 of 5
Table of Contents
Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1 of 5
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Study Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Oil Traffic in Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Overview of Tanker Oil Spills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Determination of Spill Probabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1 Spill Size Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2 Exceptionally Large Crude Oil Spills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2.1 Historical Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2.2 Exceptionally Large Crude Oil Spills in Canada . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.3 Extremely Large, Very Large and Large Crude Oil Spills . . . . . . . . . . . . . . . . . . . . . . . 18
5.3.1 Historical Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.3.2 Large Crude Oil Spills in Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.4 Special Case of U.S. West Coast Crude Oil Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.5 Small and Medium Crude Oil Spills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.6 Spills from Tankers Carrying Petroleum Products other than Crude Oil . . . . . . . . . . . . 23
5.6.1 Large Product Oil Spills from Tankers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.6.2 Very Large Product Oil Spills from Tankers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.6.2 Medium and Small Product Oil Spills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5.7 Summary of Spill Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6.Calculation and Analysis of Regional Spill Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1 Relative Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.2 National Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1. Introduction
1.1 Objective
The purpose of the study is to predict the frequency of oil spills from tankers in various regions and
areas of Canada. The information can be used to identify the regions and areas of Canada that should
be the focus of oil spill contingency planning efforts for the Canadian Coast Guard (CCG). The
information can also be helpful in deciding the level of effort required.
The analysis is an update of an unpublished study conducted by SL Ross for the CCG in 1989
entitled "Expected Frequency of Oil Spills from Tankers in or Near Canadian Waters". Versions of
this were also done for the Brander-Smith spill review panel (1990) and the Canadian Petroleum
Products Institute (1991). The focus of these studies and the current study is on particularly large
spills.
1.2 Units
This report uses two units for oil amounts – barrels and tonnes. The international oil and gas industry
primarily works with the oil volume unit of petroleum barrel (which is different than a U.S. barrel
and a British barrel). There are 6.29 petroleum barrels in one cubic metre (m3). To convert between
barrels and tonnes one needs the specific gravity of the oil because a barrel is a measure of volume
and a tonne is a measure of mass. A rough conversion for this study is 7.2 petroleum barrels per
tonne of oil. This assumes an average oil specific gravity of 0.87 or an API gravity of 30o.
The main reason for using the units of barrels in the study is that most spill statistics are taken from
publications of the U.S. Minerals Management Service which works exclusively with the oil volume
units of barrels.
-1-
2. Study Approach
There are numerous studies on marine oil-spill probability, but these have not used the same
databases and statistical approaches and hence have produced dissimilar results. The approach used
here is very simple. It assumes that there a direct correlation between spill frequency and the amount
of oil moved by vessel. This means, for example, that a system that has twice as much oil traffic as
another system will be expected to have twice as many spills.
The approach is adopted directly from a method developed by the U.S. Minerals Management
Service (MMS) for analysing large, crude oil tanker spills. Since 1983 MMS has analysed worldwide
tanker spills of crude oil in depth to determine the best risk exposure to use in normalizing spill data.
After analysing spill frequencies in terms of voyage length, ship size, oil volumes transported, spill
location, etc., it was concluded that a simple exposure of oil volumes transported (e.g., billions of
barrels) is as good as any in predicting risk. The most recent detailed reports from MMS on the
subject are provide in Anderson and Lear 1994 and Anderson and LaBelle 1994.
Canada has not experienced many large marine oil spills, so for spill-prediction purposes one must
look elsewhere for a good database on large spills. There is indeed a good database on large tanker
spills that have taken place on a worldwide basis, and this can be used as a basis for estimating
Canadian large-spill frequencies. Because worldwide statistics are used, it is assumed that tanker
safety and navigational risks in Canada are no different than those in the rest of the world.
For relatively small spills, the situation is reversed: whereas worldwide small-spill statistics are
unreliable, the Canadian government maintains a database on small spills, and it is this that is used
in the present study.
-2-
3. Oil Traffic in Canada
As stated, the expected spill frequencies for a given port area will be calculated on the basis of the
known amount of oil moved in the port, that is, the amount of oil loaded at the port and moved away,
and the amount of oil moved into the port and unloaded. Oil shipments by vessel are recorded by
Statistics Canada. On a annual, port-by-port basis the information includes: (1) the amount and type
of oil delivered (from another Canadian port or from a foreign source); and (2) the number of
shipments involved. The raw data provided by Statistics Canada are shown in four separate files in
Appendices A1 to A4, involving:
A1.
A2.
A3.
A4.
Domestic movements of all petroleum oils by port of unloading;
Domestic movements of all petroleum oils by port of loading;
International movements of all petroleum oils by port of unloading; and
International movements of all petroleum oils by port of loading.
The oil types include crude oil and various product oils, including gasoline, diesel oil, light fuel oil,
fuel oil no.1, fuel oil no.2, aviation turbine fuel, kerosene, heavy fuel oil, and bituminous mixtures.
For our purposes we assume that the risk of oil spills is identical if (a) the oil is moved into a port
and unloaded or (b) the oil is loaded at the port and moved off. As well, we assume that once in
Canadian waters, there is no difference in risk between ships arriving from international ports and
ships from domestic ports. There is a difference, however, in the risk associated with crude oil
amounts moved and product oil amounts moved, as will be shown later (this has to do with the size
of vessels involved). For this reason we keep these statistics separate.
The final results are shown in two tables – Tables 1 and 2. Other arrangements of the raw data that
were made but not used in the final analysis are included in Appendices A5 to A12.
Table 1 shows the amount of oil shipped in and out of Canadian ports, sorted by CCG Region, and
by oil type (crude oil or petroleum product). Table 2 is the same as Table 1 but shows a breakdown
for the ports in each region. The data for Grand Bank and Whiffen Head, Newfoundland, are taken
from 1999 statistics, for reasons explained below.
-3-
Table 1. Tonnage of Petroleum Loaded and Unloaded at Canadian Ports in 1998
CCG Region
Pacific
Loaded
Unloaded
Pacific Total
Central (Arctic)
Crude Oil
Tonnes
Product Oils
Tonnes
Grand Total
Tonnes
1,048,459
19
1,048,478
1,128,001.00
1,521,466
2,649,467
156,557
323,171
479,728
2,347,683
1,997,394
4,345,077
3,239,786
4,907,666
8,147,452
8,296,053
4,065,711
12,361,764
3,277,058
1,681,731
4,958,789
32,942,277
2,176,460
1,521,485
3,697,945
156,557
323,171
479,728
2,347,683
2,001,615
4,349,298
3,240,374
12,087,692
15,328,066
14,103,688
22,232,778
36,336,466
6,812,789
5,316,000
12,128,789
72,320,292
Loaded
Unloaded
Central (Arctic) Total
Central (Ont)
Loaded
Unloaded
Central (Ont) Total
Laurentian
Loaded
Unloaded
Laurentian Total
Maritimes
Loaded
Unloaded
Maritimes Total
a
Loaded
Newfoundland
Unloaded
Newfoundland Total
Grand Total
4,221
4,221
588
7,180,026
7,180,614
5,807,635
18,167,067
23,974,702
3,535,731
3,634,269
7,170,000
39,378,015
a.1999 estimate for Grand Bank/Whiffen Head
-4-
Table 2. Tonnage of Petroleum Loaded and Unloaded at Canadian Ports in 1998
Crude Oil
Product Oils
Grand Total
CCG Region
Pacific
Port
BELLA COOLA
CAMPBELL RIVER
COURTENAY
CROFTON
EAST COAST VANC ISL
ESQUIMALT
FITZ HUGH SOUND
GOLD RIVER
Unloaded
Unloaded
Unloaded
Unloaded
Unloaded
Unloaded
Unloaded
Loaded
Unloaded
NANAIMO
Unloaded
NEW WESTMINSTER
Loaded
Unloaded
PORT ALICE
Unloaded
PORT MCNEILL
Unloaded
POWELL RIVER
Unloaded
QUEEN CHARLOTTE ISLA Unloaded
SKIDEGATE
Unloaded
VANCOUVER
Loaded
Unloaded
VICTORIA
Unloaded
Pacific Total
1,048,459
19
1,048,478
Central (Arctic) ALL BEACH
ARCTIC BAY
BELCHER ISLANDS
BROUGHTON ISLAND
CAPE ASTON
CAPE DORSET
CHURCHILL
FROBISHER BAY
IGLOOLIK
INUVIK
LAKE HARBOUR
N.W.T. NES
PANGNIRTUNG
REPULSE BAY
RESOLUTE BAY
TUKTOYAKTUK
YELLOWKNIFE
Central (Arctic) Total
Unloaded
Unloaded
Unloaded
Unloaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
-5-
3,840
38,532
9,814
6,706
173,516
2,129
386
4,794
10,274
104,632
57,508
152
42,959
6,776
28,346
587
17,761
1,065,699
957,256
117,800
2,649,467
3,840
38,532
9,814
6,706
173,516
2,129
386
4,794
10,274
104,632
57,508
152
42,959
6,776
28,346
587
17,761
2,114,158
957,275
117,800
3,697,945
2,172
20,093
1,495
24,350
20,093
2,919
24,856
18,219
54,295
4,085
315
21,226
1,456
99,949
117,481
4,573
1,544
14,087
31,437
8,314
6,769
479,728
2,172
20,093
1,495
24,350
20,093
2,919
24,856
18,219
54,295
4,085
315
21,226
1,456
99,949
117,481
4,573
1,544
14,087
31,437
8,314
6,769
479,728
Table 2. Tonnage of Petroleum Loaded and Unloaded at Canadian Ports in 1998 (cont.)
Crude Oil
Product Oils
Grand Total
Central (Ont)
Port
BRITT
CLARKSON
HAMILTON
KINGSTON
KINGSVILLE
MARATHON
MORRISBURG
NANTICOKE
OAKVILLE
OSHAWA
PELEE ISLAND
PORT COLBORNE
PORT STANLEY
SARNIA
SAULT STE-MARIE
THUNDER BAY
TORONTO
WINDSOR ONT.
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Unloaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Central (Ont) Total
2
4,219
4,221
-6-
81,227
75,773
188,624
154
191,499
24,322
447
25,434
51,456
860,999
124,149
257,733
167,384
3,425
45,362
447
3,631
28,394
5,479
18,212
1,121,411
495,327
279,297
84,024
6,028
79,759
12,603
112,477
4,345,077
81,227
75,773
188,624
154
191,501
24,322
447
25,434
51,456
860,999
124,149
257,733
167,384
3,425
45,362
447
3,631
28,394
5,479
18,212
1,121,411
499,546
279,297
84,024
6,028
79,759
12,603
112,477
4,349,298
Table 2. Tonnage of Petroleum Loaded and Unloaded at Canadian Ports in 1998 (cont.)
Port
Crude Oil
Product Oils
Grand Total
Laurentian
BAIE COMEAU
Loaded
Unloaded
BLANC SABLON
Unloaded
CHANDLER
Unloaded
GASPE
Unloaded
HAVRE ST-PIERRE
Unloaded
ILES DE LA MADELEINE Unloaded
MATANE
Loaded
Unloaded
MONTREAL/CONTRECOEULoaded
Unloaded
NEW RICHMOND
Unloaded
PORT ALFRED
Unloaded
PORT CARTIER
Unloaded
QUEBEC NORTH
Loaded
Unloaded
QUEBEC NORTH SHORE Loaded
Unloaded
QUEBEC/LEVIS
Loaded
Unloaded
RIMOUSKI
Unloaded
SEPT-ILES/PTE. NOIRE
Loaded
Unloaded
TROIS-RIVIERES
Unloaded
VALLEYFIELD
Unloaded
Laurentian Total
588
579
7,179,447
7,180,614
-7-
8,673
157,404
3,676
29,158
71,267
4,794
63,402
6,719
88,822
1,524,245
2,587,419
48,135
101,607
130,580
580
54,969
50
50
1,689,458
815,042
212,957
10,061
441,137
84,271
12,976
8,147,452
8,673
157,404
3,676
29,158
71,267
4,794
63,402
6,719
88,822
1,524,833
2,587,998
48,135
101,607
130,580
580
54,969
50
50
1,689,458
7,994,489
212,957
10,061
441,137
84,271
12,976
15,328,066
Table 2. Tonnage of Petroleum Loaded and Unloaded at Canadian Ports in 1998 (cont.)
Crude Oil
Product Oils
Grand Total
Maritimes
Port
BAYSIDE
BELLEDUNE
CHARLOTTETOWN
CHATHAM
COHASSET
DALHOUSIE
GRAND MANAN
HALIFAX
NS NES/N.E. NDA
PEI NES/I.P.E NDA
PORT HAWKESBURY
SAINT JOHN
SYDNEY
YARMOUTH
Loaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Loaded
Unloaded
Unloaded
Unloaded
Maritimes Total
10,633
75,301
6,178
369,784
176,734
818,421
806,287
4,933
3,662,826
4,984,281
5,666,188
8,031,766
23,974,702
Newfoundlanda BOTWOOD
CLARENVILLE
COME BY CHANCE
CORNER BROOK
DILDO
FORTUNE
GOOSE BAY
GRAND BANK
HOLYROOD
LEWISPORTE
MARYSTOWN
NFLD NES/T.N. NDA
PORT AUX BASQUES
ST JOHNS
STEPHENVILLE
WHIFFEN HEAD
WIFFENHEAD
Newfoundland Total
Grand Total
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Loaded
Loaded
Unloaded
Loaded
Loaded
Unloaded
Unloaded
Unloaded
Unloaded
Unloaded
Loaded
Unloaded
Unloaded
Unloaded
Loaded
a. 1999 estimate for Grand Bank and Whiffen Head
-8-
3,321,005
5,569
1,454,267
1,140,441
12,562
16,844
287,974
330,393
6,524,439
1,594,111
299,969
56,565
12,361,764
124,245
9,933
3,174,237
140,845
246,166
1,964
29
80,151
2,769,988
452,480
313,264
313,263
7,170,000
39,378,015
95,779
561,898
93,544
14,724
34,365
25,728
5,049
324,760
25,372
4,958,789
32,942,277
10,633
75,301
6,178
369,784
176,734
818,421
806,287
5,569
1,459,200
4,803,267
12,562
16,844
5,272,255
5,996,581
6,524,439
9,625,877
299,969
56,565
36,336,466
124,245
9,933
3,174,237
3,461,850
246,166
1,964
29
80,151
2,769,988
95,779
561,898
93,544
14,724
34,365
25,728
457,529
324,760
25,372
313,264
313,263
12,128,789
72,320,292
A similar analysis of oil movements in 1994 was performed by Consulting and Audit Canada (CAC)
in an oil spill risk study performed for the Canadian Coast Guard in 1996 (see Figure 3.1, page 27
in CAC 1996). The following is a discussion of the similarities and differences in oil movements
between 1994 and 1998.
Total oil movements have increased from 65 million tons to 76 million tonnes. The differences in
the major ports or loading areas are shown in Table 3. These ten port areas represent about 85% of
the total amount of oil moved.
Hibernia Oil. The first major change from 1994 to 1998 is that the Hibernia field off Newfoundland
on the Grand Banks has come on stream and is producing some 2.8 million tonnes of oil per year.
The transshipment terminal at Whiffen Head did not become operational until October 1998, so most
of the oil produced in 1998 was shipped from the Hibernia facility directly to U.S. ports. Currently,
(on the basis of the record for the first six months of 1999), approximately 2/3 of Hibernia oil is
being moved directly (in 115,000 DWT tankers) to U.S. ports and 1/3 to Whiffen Head where it is
stored temporarily and then shipped in smaller vessels (78,000 DWT) to U.S. ports. Currently, then,
the Hibernia facility loadings and the Whiffen Head oil movements account for about 7 million
tonnes of oil per year, which is about 10 per cent of the total oil movements in Canada (and about
20% of the crude oil movements). It is recognized that the oil moved at Whiffen Head is counted
twice (once for unloading and once for loading), but from an oil spill risk view this is correct because
each of these movements is assumed to represent the same risk.
Port Hawkesbury. The other big change in movements is the situation at the transshipment terminal
at Port Hawkesbury. Here the main activity is bringing in crude oil from Europe in tankers of size
250,000 DWT (20 shipments from Norway in 1998) and transferring it to smaller tankers in the
80,000 DWT range. These smaller tankers then move oil to ports on the northeast coast of the U.S.
Port Hawkesbury is used in this way because the arriving tankers are either too large to be
accommodated in northeast U.S. ports or their design does not conform to new U.S. safety
regulations.
In any case, this transshipment activity has increased by over 100% since 1994. This represents a
relatively large spill risk, inasmuch as the 11 million tonnes moved annually is 14% of all oil moved
in Canada by vessel, and 26% of the crude oil moved by vessel. As with the case of Whiffen Head,
the same oil is counted twice, but this makes sense for spill risk analysis purposes.
-9-
Table 3. Oil Loadings/Unloadings at the Top Ten Canadian Ports, 1998 compared to 1994
Port
Oil loaded and unloaded,
thousand tonnes
1998
1994b
Saint John
16,150
17,826
Port Hawkesbury
11,269
5,142
Quebec
9,684
10,439
Come by Chance
6,636
5,000
Halifax
6,262
6,909
Montreal
4,113
5,450
Grand Bank (Hibernia)
4,067a
0
Vancouver
3,071
2,634
Whiffen Head (Nfld. Transshipment Terminal)
3,047a
0
Sarnia
1,621
1,432
65,920
54,832
TOTAL
a. First-half 1999 data x 2
b. Source: CAC 1996
-10-
Saint John. All of the other major ports, including Saint John, moved about the same amount of oil
in 1998 compared to 1994. Again, Saint John is the largest port by far in terms of oil movements.
Tankers of 200,000 DWT and larger bring in crude oil from various foreign sources, and tankers of
all sizes move product oil in and out of the port. This area, including the lower Bay of Fundy which
the tankers must transit to reach Saint John, must be considered the highest risk area in the country,
at least as far as oil movements are concerned.
Quebec City. The traffic to Quebec City/Levis is also a special concern and not only because the
oil volumes moved are very large. The added concern relates to the fact that crude oil carriers
destined for Quebec must travel a great distance in relatively close proximity to the Canadian
coastline. Ships must first sail in waters just south of Newfoundland, transit the Cabot Strait, move
along the Gulf of St. Lawrence, and finally must negotiate the St. Lawrence River itself. This route
adds extra risk to the Maritimes and Newfoundland regions. This study does not attempt to
quantitatively account for this transit traffic and the extra risk posed by it. Accordingly, at the end
of the quantitative risk analysis that follows, we re-visit the issue and discuss it in qualitative terms.
West Coast Crude Oil Traffic in U.S. Waters. A similar "transit" problem exists on the west coast.
A very large amount of crude oil from Alaska moves down the west coast of Canada and a
proportion is delivered to ports in Washington State (the rest moves further south).The total amount
moved into Washington ports in Puget Sound is 27.7 million tons (25.1 tonnes) (see Table B1 in
Appendix B). This is about the same amount moved into Nova Scotia and New Brunswick
combined. The traffic is not a problem as it moves down the Canadian coast because tankers keep
reasonably far offshore, but the tankers must travel into the Strait of Juan de Fuca, very close to
Vancouver Island, and into Puget Sound.
This traffic, an obvious risk to Canada, is a special case that must be handled separately, as it is in
the analysis presented in Section 5.
-11-
4. Overview of Tanker Oil Spills
Before proceeding directly to the quantitative assessment of spill probability, it useful to review the
causes and sources of ship-based spills as seen from a worldwide perspective.
The focus of the analysis is on spills from tankers. Spill sizes from non-tank ships are much smaller
than those from tankers, actually 15 times smaller on average (as shown in Table B2 in Appendix
B). Because of this, more attention is usually given to tanker spills in terms of government
regulations, contingency planning and statistical record-keeping. There is an excellent body of spill
statistics related to the tanker business, especially involving crude oil, but much less related to spills
from other ships. Accordingly, it is convenient here to deal with tanker spills exclusively.
Tanker accidents that lead to spills can be divided into those that occur as a result of (1) operations
in ports or oil terminals and (2) casualties involving groundings, collisions, explosions, and the like.
As shown in Table 4 (from ITOPF 1999) most spills from tankers result from routine operations,
such as loading, discharging and bunkering, that normally occur in ports or at terminals. The majority
of these operational spills are small, with some 85 per cent involving quantities less than 50 barrels
(7 tonnes). Accidents involving collisions and groundings generally give rise to much larger spills.
It is these large spills resulting from casualties that are of prime interest in this study.
It is calculated from Table 4 that 76% of accidents leading to the larger spills (>5000 barrels)
resulted from collisions and groundings, and 24% from hull failures, fires and explosions. Similar
statistics are shown in Table 5. (This is from a classic study by Card et al. that is old (1975) but still
of relevance today.) As shown, in the four-year period of 1969-1973 there were over 3000 recorded
accidents of tankships, 452 of which led to the discharge of over 770,000 tons of oil into the marine
environment. This averaged about two accidents per day worldwide. The percentage of casualties
that involved collisions, rammings and groundings is seen to be 65%. Also seen is the fact that about
14 % of tanker casualties resulted in some outflow of oil (452/3183). This number is consistent with
the results of more recent studies on tanker accidents (CCG 1991, USCG 1994).
Fortunately, the safety record of tankers have improved considerably since the early 1970s. This is
shown in Figure 1 (also from ITOFP 1999). It is seen that the number of tanker spills over 700
tonnes in size (5000 barrels) in the 1970s averaged about 24 spills per year, and in the 1980s the
average was about 8 spills per year, a three-fold decrease.
-12-
Table 4. Incidence of Tanker Spillsa by Cause, 1974-1998
<50 barrels
or <7 tonnes
50-5000 bbl
or 7-700 tonnes
>5000 bbl
or >700 tonnes
Total
Loading/discharging
2756
291
17
3064
Bunkering
541
24
0
565
Other operations
1162
47
0
1209
Collisions
150
229
85
464
Groundings
219
191
103
513
Hull failures
552
73
40
665
Fires & explosions
149
16
19
184
OTHER
2213
159
34
2406
Total
7742
1030
298
9070
OPERATIONS
ACCIDENTS
Source: ITOPF 1999 – www.itopf.com
a. Database includes crude oil spills and product oil spills
Figure 1. Number of Spills over 700 tonnes
40
Number of spills
35
30
1970-79
24.1spillsperyear
onaverage
25
20
1980-89
8.8spillsperyear
1990-98
onaverage
7.6spillsperyear
15
onaverage
10
5
0
Year
-13-
Source: ITOPF 1999
Table 5. Tankships (over 3,000 DWT) Involvements 1969-1973a
Involvement
Type
Total
Number of
Involvements
Percent of
Involvements
Number
Resulting in
Outflow
Percent of
Oil Outflow
Involvements
Amount of
Oil Outflow
(LT)
Number of
Total Losses
Outflow
from Total
Losses
Breakdown
355
11
11
2
29,940
2
29,350
Collision
744
24
126
28
185,088
7
140,779
Explosion
104
3
31
7
94,803
11
88,780
Fire
197
6
17
4
2,935
1
1,250
Grounding
790
25
123
27
230,806
12
134,449
Ramming
473
15
46
10
13,645
0
0
Structural Failure
515
16
94
21
339,181
15
322,519
5
-
4
1
54,911
3
54,790
3,183
100
452
100
951,309
51
771,917
Other
TOTALS
Source: Card et al. 1975
a.
Database includes both crude oil tankers and product oil tankers
5. Determination of Spill Probabilities
The end objective is to calculate spill probabilities, or predictions of spills per year, for the oil traffic
reported in Section 3. The first step is to derive, for spills of various size, spill frequencies in terms
of spills per billion barrels of oil moved (or billion tonnes of oil moved). This is done in this chapter.
The next step is simply to multiply the tonnage moved per year by the calculated spill frequencies.
This yields the predicted spill rates. In the analysis, crude oil and petroleum product are considered
separately for a number of reasons explained later.
5.1 Spill Size Classification
For convenience, six spill size categories are selected and analysed. The first two categories are for
“exceptionally large” and "extremely large" spills, arbitrarily defined as spills larger than 200,000
barrels (27,800 tonnes) and 100,000 bbl (13,900 tonnes) respectively. Good worldwide statistics are
available for such spills. The third and fourth categories are for “very large” and “large” spills,
defined by the U.S. Minerals Management Service as spills larger than 10,000 barrels (1390 tonnes)
and 1000 barrels (139 tonnes) respectively. The fourth category is for spills in the range of 50 to 999
bbl, and the fifth category is for spills in the 1 to 49 bbl category. In summary, the spill size
classifications used in this study are:
Exceptionally Large spills:
Extremely Large spills:
Very Large spills
Large spills:
Medium spills:
Small spills:
>200,000 bbl
>100,000 bbl
>10,000 bbl
>1000 bbl
50 - 999 bbl
1 - 49 bbl
(>27,800 tonnes)
(>13,900 tonnes)
(>1390 tonnes)
(>139 tonnes)
(6.9 - 138.9 tonnes)
(0.14 - 6.89 tonnes)
Note that the top four categories are cumulative, for example, the large-spill category (>1000 bbl)
includes the very large, extremely large and exceptionally large spills, and the very large category
includes extremely large spills, and so on.
-15-
5.2 Exceptionally Large Crude Oil Spills
5.2.1 Historical Record
Exceptionally large spills, however familiar to the public, are unlikely events: there have only been
53 such spills ever, as shown in Table 6. (The oil volumes are expressed in tonnes; multiply by 7.2
for barrels.) the average size of the exceptionally large (>200,000 bbl) spills noted in the table is
74,900 tonnes (539,000 barrels) and the median size is 53,000 tonnes (382,000 barrels).
No exceptionally large spill occurred before 1967 and only one occurred between 1981 and 1987.
In 1988 two tanker total-losses occurred in the NW Atlantic, Odyssey and Athenian Venture, the
latter mentioned later in a Canadian context.
Over the past ten years the following nine exceptionally large spills (>200,000 bbl or >28,600
tonnes) occurred. In March 1989 the Exxon Valdez went aground spilling some 250,000 barrels
(35,000 tonnes) of crude oil in Prince William Sound, Alaska, and in late December 1989 the Kharg
5 tanker spill happened off the coast of Morocco involving 540,000 bbl (72,000 tonnes). No
exceptionally large spills occurred in 1990, but in 1991 two major tanker spills happened off Italy:
the Agip Abruzzo and the Haven. Also in 1991 the ABT Summer, carrying 260,000 tonnes of crude
oil, exploded and sank in the SE Atlantic, making it the second largest tanker oil "spill" in history;
as with the Agip Abruzzo, much of the oil did not spill on water but rather either burned, or sank with
the tanker in 5-km deep water. Two exceptionally large spills occurred in 1992 (the Aegean Sea and
the Katina P.) and only two have occurred since, both off U.K. waters: the Braer (85,000 tonnes)
off the Shetland Islands in 1993 and the Sea Empress (72,000 tonnes) off Wales in 1996. In
summary, an average of 1.6 exceptionally large spills (>200,000 bbl), many involving total losses,
have occurred annually over the past 34 years since the Torrey Canyon spill in 1967. This has
reduced over the past ten years to one such spill per year. No exceptionally large spill has occurred
since 1996.
Nearly all the spills in Table 6 involved crude oil. It is known that 193.6 billion barrels of crude oil
were moved by tanker from the period 1974 to 1995 (Fearnley's World Bulk Trades Report–1999).
The table shows that 35 exceptionally large spills occurred during this period. Therefore, the
frequency of exceptionally large tanker spills during this 22 year period was 35/(193.6 x 109)= 0.18
spills per billion barrels transported. Based on recent experience in the 1980s and 1990s, the
frequency has dropped to about 0.1 spills per billion barrels of crude oil moved.
-16-
Table 6. World's Largest Oil Spills from Tankers, 1942-1999
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
Tanker Name
Location
Atlantic Empress
ABT Summer
Castillo de Bellver
Amoco Cadiz
Haven
Odyssey
Torrey Canyon
Sea Star
Irenes Serenade
Urquiola
Texaco Denmark
Hawaiian Patriot
Independenta
Julius Schindler
Braer
Jakob Maersk
Kharg 5
Agip Abruzzo
Sea Empress
Aegean Sea
Katina P.
Nova
Wafra
Epic Colocotronis
Sinclair Petrolove
Assimi
Metula
Andros Patria
World Glory
British Ambassador
Pericles GC
Ennerdale
Tadotsu
Mandoil II
Napier
Trader
Texas Oklahoma
Irene’s Challenge
St. Peter
Juan A. Lavalleja
Thanassis A.
Exxon Valdez
Burmah Agate
Athenian Venture
Golden Drake
Chryssi
Keo
Paceoan
Caribbean Sea
Grand Zenith
Cretan Star
Team Castor
Argo Merchant
Tobago
SE Atlantic
Africa
France
Italy
NW Atlantic
U.K.
Gulf of Oman
Greece
Spain
Belgium
Pacific Ocean
Turkey
Portugal
U.K.
Portugal
Morroco
Italy
U.K.
Spain
Mozambique
Arabian Gulf
Africa
Puerto Rico
Brazil
Oman
Magellan Straits
Spain
S. Africa
Japan
Qatar
Indian Ocean
Strait of Malacca
U.S. East Coast
Chile
Greece
NW Atlantic
Pacific
SE Pacific
Algeria
NW Pacific
Alaska
Texas
NW Atlantic
NW Atlantic
NW Atlantic
NW Atlantic
NW Pacific
E. Pacific
NW Atlantic
Indian Ocean
France
Cape Cod ( USA)
-17-
Approximate Size (tonnes)
Year
280,000
260,000
260,000
230,000
140,000
130,000
120,000
120,000
120,000
110,000
100,000
99,000
93,000
90,000
85,000
80,000
72,000
74,000
72,000
72,000
72,000
72,000
65,000
57,000
56,000
53,000
53,000
47,000
45,000
45,000
44,000
43,000
42,000
40,000
36,000
35,000
35,000
35,000
35,000
35,000
35,000
35,000
34,000
32,000
31,000
31,000
31,000
31,000
31,000
31,000
31,000
31,000
31,000
1979
1991
1983
1978
1991
1988
1967
1972
1980
1976
1971
1977
1979
1969
1993
1975
1996
1991
1996
1992
1992
1985
1971
1975
1960
1983
1974
1978
1968
1975
1983
1970
1978
1968
1973
1972
1971
1977
1976
1980
1994
1989
1979
1988
1970
1970
1969
1969
1977
1976
1976
1979
1976
5.2.2 Exceptionally Large Crude Oil Spills in Canada
It is now important to ascertain whether the spill frequencies determined from worldwide statistics apply
to Canadian waters. Since 1974, tankers have moved approximately 4 billion barrels of crude oil to
Canada. Such tankers should have had 0.18 x 10-9 x 4 x 109 or 0.7 exceptionally large tanker spills since
1974. If 50% of spills associated with Canadian-bound tankers occur on the outbound portion of the
tanker's journey (in the Middle East, North Sea, Nigeria, etc.) and 50% on the inbound portion to Canada,
then Canada had a 35% chance (0.5 x 0.7) of having such a spill over the past 25 years. Fortunately, this
did not appear to happen. It is interesting to note, however, that the Athenian Venture tanker that broke
up and lost 230,000 barrels (32,000 tonnes) of crude oil in the northwest Atlantic off Canada in late 1988
was on the inbound portion of its journey to Come-by-Chance, and could be considered a "Canadian"
spill from a statistical viewpoint. Thus, in a sense, Canada has had at least one exceptionally large crude
oil spill in the past 25 years.
5.3 Extremely Large, Very Large and Large Crude Oil Spills
5.3.1 Historical Record
Because large, very large, and extremely large crude oil spills have been infrequent or non-existent in
Canada, it is necessary to rely on worldwide statistics for these spill categories. It is known that about
164.4 billion barrels of crude oil were transported on a worldwide basis from 1974 to 1992, as shown in
Table 7. Table 7 also shows the number of extremely large (>100,000 bbl), very large (>10,000 bbl) and
large crude oil spills (>1000 bbl) that have occurred during this 19-year period, both “in port”, meaning
in harbours or at piers, and “at sea”, meaning away from ports either in restricted waters or in open
waters.
Using the statistics in Table 7 and other statistics, Anderson and LaBelle (1994) calculated oil spill
frequencies for the three different spill categories, and these are shown in Table 8 for the worldwide
situation. Note that both “average” and “median” size spill statistics are provided in Table 8. The average
size spill is derived by simply dividing the total volume spilled by the total number of spills. The median
spill size in a given category means that 50% of the spills were smaller than the median size and 50%
were larger. The average size is much larger than the median size because the former number is heavily
skewed by the handful of historical tanker spills of exceptionally large size.
-18-
Table 7. Number of worldwide crude oil tanker spills $1000 bbl and crude oil movements, 1974-1992
Number of spills in port
All
1000-9999
10 000-99 999
100 000 bbl
1000-9999
10 000-99 999
100 000 bbl
bbl
bbl
and greater
bbl
bbl
and greater
Crude oil
Spills
movements
per
(109 bbl)
109 bbl)
Year
spills
1974
19
5
2
1
6
3
2
10.2
1.9
1975
19
2
0
3
5
7
2
9.3
2.0
1976
18
3
0
1
4
4
6
10.5
1.7
1977
15
1
2
1
3
3
5
10.7
1.4
1978
17
3
1
0
3
4
6
10.5
1.6
1979
22
3
2
2
4
5
6
11.0
2.0
1980
11
1
1
1
3
2
3
9.7
1.1
1981
7
3
1
0
3
0
0
8.5
0.8
1982
6
2
0
1
3
0
0
7.3
0.8
1983
13
4
1
0
1
4
3
6.9
1.9
1984
6
1
3
0
1
1
0
6.8
0.9
1985
5
1
2
0
1
0
1
6.4
0.8
1986
6
2
0
0
1
3
0
7.2
0.8
1987
11
3
1
0
4
3
0
6.8
1.6
1988
6
1
3
0
1
0
1
7.4
0.8
1989
12
3
0
0
1
5
3
8.0
1.5
1990
8
5
0
0
1
2
0
8.7
0.9
1991
6
0
0
1
2
1
2
9.2
0.7
1992
6
3
0
1
1
1
0
9.3
0.6
46
19
12
48
48
40
164.4
1.3
Total
a
Number of spills at sea
a
213
213 spills $1000 bbl totaling 22 191 00 bbl; includes 38 spills in U.S. waters totaling 1 868 800 bbl; excludes inland spills. Source: Anderson and LaBelle 1994
Table 8. Worldwide Tanker Spill Rates, 1974-1992
Tanker spillsa
Number
of spills
Average
spill size
(bbl)
Median
spill size
(bbl)
Spill Rateb
(spills per 109 bbl)
77
136
213
58 300
130 100
104 200
6400
22 000
15 000
0.47
0.83
1.30
31
88
119
139 500
198 700
183 300
50 000
88 400
73 300
0.19
0.53
0.72
12
40
52
310 300
392 900
373 800
251 000
243 600
243 600
0.07
0.24
0.31
$1000 bbl
In Port
At Sea
All Spills
$10 000 bbl
In Port
At Sea
All Spills
$100 000 bbl
In Port
At Sea
All Spills
a
b
Crude oil spills only, excludes barge and inland spills (1 bbl = 0.159 m3).
Based on movement of 164.4 x 109 bbl crude oil.
Source: Anderson and LaBelle 1994
Table 9. Worldwide Tanker Spill Frequencies for Large Spills (>1000 bbl) in Port, Restricted
Waters (< 50 nm) and Open Sea (>50 nm), 1974-1992
Number of
spills
Average spill
size (bbl)
Spill rate (spills per 109
bbl)
In Port
77
58 300
0.47
Restricted Waters
110
122 000
0.67
Open Sea
26
198 000
0.16
All Locations
213
104 200
1.30
Location
-20-
For interest, spill rates for large and very large tanker spills in U.S. coastal and offshore waters are shown
in Appendix B in Table B3. Similarly, the spill rates for tankers involved in North Slope crude oil trade
operating out of Valdez, Alaska, are shown in Table B4. These tables show lower frequencies for both
these situations compared to the worldwide situation.
Note again the dramatic decrease in spill frequency when comparing spills in the 1970s to spills in the
1980s and beyond.
It is now useful for later analysis to refine Table 8 in terms of the “at sea” statistics. In the late 1970s and
early 1980s MMS used to break the “at sea” statistics into the two categories of spills in “restricted
waters,” defined by MMS as waters less than 50 nautical miles from land (93 kilometres) and spills in
the “open sea”, that is, beyond 50 nmiles of land. In these earlier studies it was shown that spills in the
open sea represented about 10% of the total number of large spills. This low percentage is understandable
because most tanker spills occur during loading and unloading operations in port, or as a result of
collision and grounding accidents, which mostly take place in harbours and restricted waters. Large tanker
spills in the open sea are most likely to result from hull failures during poor weather, or fires and
explosions. Table 4 shows that spills resulting from such accidents represent about 13% of total spills
where the cause is known.
In any case, it is of interest for later use to break down the “at-sea” statistics in Table 8 into the categories
of “restricted waters” and “open sea”. The analysis is limited to “large” spills, that is, spills larger than
1000 barrels. Table 8 shows that 136 such spills occurred “at sea” (restricted waters and open sea) during
the time frame of 1974 to 1992. In Anderson and Lear (1994) spill locations are noted for all spills in the
database. The data show that of the 136 spills, 26 can be said to have occurred in the open sea, beyond
50 nmiles of land. This represents 12% (26/213) of all large spills during the period. Table 9 summarizes
the reworked version of Table 8 including average spill sizes.
5.3.2 Large Crude Oil Spills in Canada
It is useful again to check the Canadian record against the worldwide one, this time with respect to large
spills (>1000 bbl). Table 8 shows that the worldwide statistic for large tanker spills of crude oil is 1.3
spills per billion barrels transported. Assuming as before that 4 billion barrels of crude oil have been
moved by tankers to Canada since 1974, and assuming that 50% of spills associated with Canadian-bound
-21-
tankers will occur on the outbound journey of the tanker and 50% in Canada, such tankers should have
had 1.3 x 10-9 x 0.5 x 4 x 109 or 2.6 large (>1000 bbl) tanker spills of crude oil during this period. Canada
has indeed suffered two large crude oil spills (>1000 barrels). One occurred in 1974 (the Imperial Sarnia
tanker spill off Brockville, Ontario) involving a discharge of 2100 barrels of oil, and the other occurred
in 1988 (the Czantoria tanker spill in the port of Quebec) involving about 3300 barrels. There is also the
exceptionally large Athenian Venture spill which occurred in the Northeast Atlantic far off Canada, but
still is a Canadian spill, statistically speaking.
5.4 Special Case of U.S. West Coast Crude Oil Traffic
About 25 million tonnes of crude oil per year move into ports in Puget Sound, Washington, mostly from
the Port of Valdez, Alaska. This traffic comes very close to the south coast of Vancouver Island. The
following is an attempt to estimate the likely occurrence of large spills from this traffic that could impact
Canadian waters and coastlines.
Referring back to Table 9, it will be assumed that the at-sea component of risk for the Alaska-toWashington traffic is negligible because tankers remain far offshore before approaching the Strait of Juan
de Fuca.. Similarly, it will be assumed that the "in port" component is not a risk to Canada. What remains
then is the risk associated with the tankers sailing in restricted waters, meaning less than 50 nm from land.
This risk is shared by the incoming and outgoing parts of the journey, namely the waters south of
Vancouver Island as tankers approach and enter Puget Sound, and the restricted waters that tankers must
negotiate on leaving Valdez after loading. Therefore, the estimated frequency of large (>1000 bbl) crude
oil spills from this traffic that represent a threat to Canada is simply 0.5 x 0.67 = 0.34 spills per billion
barrels transported.
The volume of oil moved is about 25 million tonnes per year or approximately 0.18 billion barrels per
year. The estimated annual spill rate of large spills (>1000 bbl) is then 0.18 x 0.34 = 0.061 spills per year.
This is equivalent to one such spill every 16 years. This number will be brought forth in the final analysis
of the report.
-22-
5.5 Small and Medium Crude Oil Spills
Smaller spills occur much more frequently than do spills larger than 1000 barrels. Spill frequencies for
small and medium size oil spills can be calculated by considering Canadian spill statistics which are
available from NATES (the National Analysis of Trends in Emergencies System, maintained by the
Environmental Emergency Program Division, Management and Emergencies Branch, Environment
Canada, Ottawa). The data in NATES for small and medium size spills of crude oil are shown in Table
10. Crude oil spills larger than 1000 barrels are also shown for completeness.
The statistics in Tables 10 can be transformed into spill frequencies in terms of spills per billion barrels
transported by considering the oil volumes transported in Canada. The volume of crude oil traffic in
Canada over the time period was about 22 million tonnes per year or about 0.165 billion barrels per year.
This crude oil was generally imported to (the East Coast) or exported from (the West Coast) of Canada
by tanker; there were virtually no crude oil tanker shipments from a Canadian port to another Canadian
port. The spill frequency results are shown in Table 11. These frequencies are associated with the entire
tanker's journey, that is, both the inbound and outbound portions of a tanker's journey. In other word the
spills noted in Table 10 are associated with only half of the tankers' voyages. Spills associated with the
other half are presumed to take place outside Canada mostly in the foreign port areas that are at the other
end of the journey.
5.6 Spills from Tankers Carrying Petroleum Products other than Crude Oil
Analysing and predicting tanker spills of product oil is more difficult than doing so for crude oil. There
are two problems. First, the international data base for product spills is not as good as that for crude oil
spills. Second, much of the product oil movements in the world take place coastwise within countries.
This traffic, mostly involving small vessels, is not often well recorded, and the amounts of oil moved in
this fashion are not easy to calculate.
For this reason we again use Canadian statistics from NATES (the National Analysis of Trends in
Emergencies System, maintained by Environment Canada) to derive the necessary spill frequencies. The
major problem with this, for very large spills, is that there have been only a couple of such spills in
Canada, and it is questionable as to whether one can base a prediction on only two data points.
-23-
Table 10. Spills of Crude Oil from Tankers in Canadian Waters (1973-1996)
Spill Size Range (bbl)
Number of Spills
Average Spill Size (bbl)
>1000
2
2560
50-999
6
233
1-49
31
10.4
Table 11. Crude Oil Tanker Spill Frequencies (per billion bbl transported) for Three Spill Size
Ranges
Spill Size Range (bbl)
Spills/Billion Barrels Transported
>1000
1.3 (from worldwide statistics)
50-999
3.0
1-49
15
-24-
5.6.1 Large Product Oil Spills from Tankers
Table 12, derived from data available in NATES, lists all large product oil spills from tankers that
occurred during the period 1973 to 1996. Note that no large spill has occurred since 1986.
The average size was 6200 barrels and the median spill size was 1600 barrels. The total number of spills
is 12, which equates to an annual spill frequency of 12/24 or 0.50 product oil spills (>1000 bbl) per year.
This can be transformed into spill frequencies in terms of spills-per-billion-barrels-transported by
considering the oil volumes transported during the period. The volume of product oil traffic in Canada
over the time period was about 0.20 billion barrels per year. This was all the oil loaded at Canadian ports
plus all the oil unloaded. Consider that approximately 50 percent of the product oil over the period moved
between Canadian ports and 50 percent was imported or exported (in 1998 the actual value was 55%).
This means that 0.10 billion barrels were imported and unloaded at a Canadian port, or loaded at a
Canadian port and exported, and 0.10 billion barrels were loaded and unloaded in domestic trade. From
a spill perspective only half of the import/export movements occurred in Canada waters (the other half
occurred in the foreign waters), so only half of the spill risk for these spills occurred in Canada. For the
domestic shipments the volume of oil actually shipped or moved was one-half the volume reported
because it is counted once when loaded and once when unloaded, so the actual volume moved internally
was 0.05 billion barrels. Therefore, for statistical risk exposure purposes, the total volume moved was
0.05 x 109 +0.05 x 109 = 0.10 x 109 barrels per year.
Having this number allows the calculation of the spill frequencies. The frequency of large (>1000 bbl)
product oil spills in Canada has been:
(0.50 spills/yr)/[0.1 billion barrels/yr) = 5.0 spills per billion barrels moved.
Again, note that this frequency applies to the entire tanker's journey, i.e., both the inbound and the
outbound portions.
-25-
Table 12.
Accidental Spills of Product Oil Larger than 1000 bbl from Tankers in Canadian
Waters (1973 -1996)
Tanker Name
Spill
Year
Product
Spilled
Barrels
Spilled
Cause
Location
NTCL
1974
No. 2 Fuel Oil
1000
grounding
Bushell Inlet, Sask.
Imperial St. Clair
1976
No. 2 Fuel Oil & Gasoline
1650
grounding
Parry Sound, Ont.
Imperial Bedford
1977
No. 2 Fuel Oil
1360
equip. failure
Charlottetown, PEI
Marystown, Nfld.
Golden Eagle
1977
Nos. 4, 5 Fuel Oil
1430
equip. failure
????
1977
No. 2 Fuel Oil
2790
intentional
???, BC
Canso Light
1979
No. 2 Fuel Oil
5880
grounding
Canso Strait, N.S.
Kurdistan
1979
No. 6 Fuel Oil
49,900
material fail.
Cabot Strait, N.S.
Imperial Acadia
1982
No. 2 Fuel Oil
1810
grounding
Port aux Basque, Nfld.
Irving Eskimo
1983
No. 6 Fuel Oil
1580
grounding
Sept Iles, Que.
Manolis L.
1985
Nos. 4, 5 Fuel Oil
3250
sinking
Blow Hard Rock, Nfld.
Pointe Levy
1985
No. 6 Fuel Oil
1650
grounding
Matane, Que.
Irving Wood
1986
Gasoline
1630
tank leak
Miquelon Harbour, N.S.
Table 13. Spills of Petroleum Product from Tankers in Canadian Waters (1973 -1996)
Spill Size
Range (bbl)
Number of
Spills
Average Spill
Size (bbl)
>1000
50-999
1-49
12
58
173
6320
216
10.3
Table 14. Frequencies for Product Oil Tanker Spills in Canada, 1973 -1996
Spill Size Range (bbl)
Spills/Billion Barrels Transported
>1000
50 to 999
1 to 49
5.0
24.6
72
-26-
5.6.2 Very Large Product Oil Spills from Tankers
Because the average size of tanker carrying product oil in Canada is about 10,000 DWT we will assume
that the chances of an exceptionally large spill of product oil (> 27,800 tonnes) spill of product oil is very
small or negligible. What remains is a an extremely large spill (> 13,900 tonnes) and a very large spill,
defined as larger than 10,000 barrels or 1390 tonnes.
The two largest oil spills in Canadian history were the Arrow spill in 1970 (officially 108,000 barrels or
about 15,000 tonnes) and the Kurdistan spill in 1979 (about 7000 tonnes). This means that Canada has
suffered from one extremely large spill and two very large spills. (Remember that the very large spill
range also includes the extremely large spill range). This means that on average 1/30 = 0.033 extremely
large spills/year have happened since 1970 and 0.067 very large spills. We will assume, as we did for
the case of exceptionally large spills, that the spill rate over the 1980s and 1990s has been approximately
50% of the average of the past 20 to 30 years. This means the annual spill rates should be halved to
represent today's situation.
For calculation purposes we will make the same assumptions as we did in the previous section about the
annual movement of product oil in Canada. The following equations then apply:
The frequency of extremely large (>100,000 bbl) product oil spills in Canada is:
(0.033/2 spills/yr)/[0.1 billion barrels/yr) = 0.167 spills per billion barrels moved.
And the frequency of very large (>10,000 bbl) product oil spills in Canada is:
(0.067/2 spills/yr)/[0.1 billion barrels/yr) = 0.330 spills per billion barrels moved.
Again, note that these frequencies apply to the entire journey of a tanker, i.e., both the inbound and the
outbound portions.
-27-
5.6.2 Medium and Small Product Oil Spills
The data in NATES from medium spills (50 - 999 bbl) and small spills (1 - 49 bbl) are shown in Table
13. Spills larger than 1000 barrels are also shown for completeness. These number can be transformed
into spill frequencies in terms of spills-per-billion-barrels-transported by using the same logic as before
for the large spills. The results for all are summarized in Table 14.
5.7 Summary of Spill Frequencies
Here, all the spill frequency numbers generated above are summarized and converted to the units of
"spills per billion tonnes loaded or unloaded" so they can be used directly with Tables 1 and 2 to calculate
expected spill rates (spills per year) for the specific port areas of Canada, for the CCG regions and for
Canada as a whole. The results are shown in Table 15. Please note the following:
1.
The spill frequencies shown in Tables 8 and 14 represent spills over an entire tanker's journey
(including loading and unloading). Table 15 gives spill frequencies that be can be used directly with
the loading/unloading volumes from Statistics Canada reported here. These frequencies are half the
numbers shown in Tables 8 and 14. This is because oil loaded in one port in Canada that is unloaded
in another is counted twice in Tables 1 and 2, once as a loading and once as an unloading.
2.
Remember that frequencies for spills > 1000 barrels include the higher ranges. They are not additive.
However, the lower three ranges (1- 49 bbl, 50 - 999 bbl and >1000 bbl) are additive, and the sum
represents the frequency of all spills.
3.
Product oil spill larger than 200,000 barrels are not possible, so the frequency was set at zero.
Frequencies for the product oil categories of spills > 100,000 bbl and spills > 10,000 bbl are of
dubious value because they were calculated on the basis of one and two spills respectively.
-28-
Table 15. Spill Frequencies (Inbound or Outbound Journeys) and Average and Mean Spill Sizes for Six Categories
Crude Oil Spills
Spill Frequencyb
spills/ 109 bbl
spills/109 T
loaded or
unloaded
loaded or
unloaded
Exceptionally
Large, >200,000 bbl
(>27,800 T)
0.050a
0.36
Extremely Large,
>100,000 bbl
(>13,900 T)
0.155
Very Large,
>10,000 bbl (>1390
T)
0.36
Large, >1000 bbl
(>139 T)
0.65
Medium, 50-999
bbl (6.9-138.9 T)
1.5
Small, 1-49 bbl
(0.14-6.89 T)
7.8
Spill Category
1.12
2.59
4.68
10.8
56.2
Product Oil Spills
Spill Frequencyb
Spill Size
Average
Median
539,000 bbl
382,000 bbl
(74,900 T)
(53,000 T)
374,000 bbl
244,000 bbl
(51,900 T)
(33,800 T)
183,000 bbl
73,300 bbl
(25,5000 T)
(10,200 T)
104,000 bbl
15,000 bbl
(14,500 T)
(2100 T)
233 bbl
132 bbl
(32 T)
(18 T)
10.4 bbl
5 bbl
(1.4 T)
(0.7 T)
Spill Size
spills/ 109 bbl
spills/109 T
loaded or
unloaded
loaded or
unloaded
0
0.083
0.167
2.5
12.3
36
Average
Median
0
0
0
0.594
108,000
bbl
108,000
bbl
(15,000 T)
(15,000 T)
79,000 bbl
79,000 bbl
(11,000 T)
(11,000 T)
6320 bbl
1688 bbl
(878 T)
(234 T)
216 bbl
124 bbl
(30 T)
(17 T)
10.3 bbl
5.8 bbl
(1.4 T)
(0.8 T)
1.20
18
88.6
260
a. Numbers are kept at three significant digits for calculation purposes.
b. These values are half the spill frequencies normalized by volumes moved because a movement includes a loading and an unloading.
-29-
6.Calculation and Analysis of Regional Spill Rates
The frequency numbers in Table 15 are combined with the shipping statistics in Table 1 to produce
statistics on the number of spills per year that are likely to happen in each CCG region for the six
categories of spill size range. The results are shown in Table 16 (at the end of the section).
To obtain a breakdown of similar statistics for any specific port within the regions, simply multiply the
frequencies in Table 15 by the port volumes.
Not included in the table is the spill risk calculated earlier (in Section 5.4) for the movement of crude oil
into Puget Sound just south of Vancouver Island. The volume of oil moved is about 25 million tonnes
per year. The estimated annual spill rate of large spills (>1000 bbl) was calculated to be 0.061 spills per
year. This is equivalent to one such spill every 16 years.
6.1 Relative Risk
The following conclusions can be made about the relative risk of oil spills across the country.
1.
The Maritimes region by far has the greatest risk of spills. Literally half the total risk for the country
is in the Maritimes region. The risk picture is even worse than it seems from Table 16 because the
traffic to Quebec City poses as much a risk to the Maritimes Region as is does to the Laurentian
Region because tankers must transit the former region with the crude oil deliveries to Quebec. As
seen from Table 9, the risk of large spills in "restricted waters" is actually greater than the risk within
ports, and the spill sizes are substantially larger. It is not surprising that the two largest oil spills in
Canadian history, the Arrow spill in 1970 (about 15,000 tonnes) and the Kurdistan spill in 1979
(about 7000 tonnes) occurred in this region.
2.
The Newfoundland region would be ranked number two even though ports in the Laurentian Region
load and unload more oil. The reason is twofold. First, the volume of oil moved in the region is
relatively large and is growing quickly as the oil industry produces more Grand Bank oil and moves
it by tanker to Whiffen Head through Placentia Bay. Second, much traffic to the Quebec and
-30-
Maritime ports must pass relatively close to the coast of Newfoundland, and recent experiences with
oiled birds washing ashore from illegal dumps from some this traffic show that the prevailing
currents and winds can indeed push a large spill to the south coast of the province.
3.
Quebec would be next for obvious reasons: a substantial amount of oil is moved in the province, the
second largest amount in the country. The region is also troubled by having to deal with spills in the
St. Lawrence River. Spills in rivers are always more difficult to control than spills in low current
situations, and spills in rivers can quickly be forced ashore by winds and oil can smear long stretches
of coast as the oil.
4.
For the same reason the St. Clair River is Ontario is a hot spot because a substantial amount of oil
is moved in the river to and from Sarnia (1.5 million tonnes loaded and unloaded in 1998), and the
river has very high currents, making spill control very difficult.
5.
Finally, the Pacific region would have about the same risk of the Central region, and perhaps more
because of the U.S. traffic to Puget Sound.
6.2 National Assessment
Remember that the spill rates for the larger crude oil spills in Table 16 were derived on the basis of
international statistics, and may not exactly apply to Canada, and that the spill rates predicted for the very
large and extremely large product spills are based on only one or two spill events, and hence are of
dubious value. In any case, the table shows that the chance of a large spill (>1000 bbl) for the country as
a whole is about one per year. This would not be a trivial spill inasmuch as its average and median spill
sizes are estimated to be 14,500 tonnes and 2100 tonnes, respectively.
The spill of particular interest to the Coast Guard is likely to be the very large spill (>10,000 bbl) because
this spill size range produces a median spill size of about 10,000 tonnes. This has been the size of interest
for planning purposes in Canada ever since the Brander-Smith panel exercise 10 years ago, and is close
to the spill size of the two largest spills already experienced by Canada. Table 16 shows that this spill size
has a probability of occurrence of one in seven years.
-31-
Table 16. Number of Spills per Year for Canadian Coast Guard Regions
Volume
6
(10 tonnes)
crude
product
CCG Region
Number of Spills per Year
Size Range
Size Range
Size Range
Size Range
> 1,000 bbl
> 10,000 bbl > 100,000 bbl > 200,000 bbl
4.680E-03
2.592E-03
1.116E-03
3.600E-04
1.800E-02
1.20E-03
5.976E-04
0.00E+00
Size Range
1 - 49 bbl
5.616E-02
2.592E-01
Size Range
50 - 999 bbl
1.080E-02
8.856E-02
1.048
2.649
3.698
0.059
0.687
0.746
0.0113
0.2346
0.2460
0.0049
0.0477
0.0526
2.72E-03
3.19E-03
0.0059
1.17E-03
1.58E-03
0.0028
3.77E-04
0.00E+00
0.0004
0.000
0.480
0.480
0.000
0.124
0.124
0.0000
0.0425
0.042
0.0000
0.0022
0.002
0.00E+00
5.77E-04
5.77E-04
0.00E+00
2.87E-04
2.87E-04
0.00E+00
0.00E+00
0.00E+00
0.004
4.345
4.349
0.000
1.126
1.126
0.0000
0.3848
0.3848
0.0000
0.0782
0.0782
1.09E-05
5.22E-03
5.24E-03
4.71E-06
2.60E-03
2.60E-03
1.52E-06
0.00E+00
1.52E-06
7.181
8.147
15.328
0.403
2.112
2.515
0.0776
0.7215
0.7991
0.0336
0.1467
0.1803
1.86E-02
9.80E-03
2.84E-02
8.01E-03
4.87E-03
1.29E-02
2.88E-06
0.00E+00
2.88E-06
Pacific
Crude Oils
Product Oils
Pacific Total
Central (Arctic)
Crude Oils
Product Oils
Central (Arctic) Total
Central (Ont)
Crude Oils
Product Oils
Central (Ont) Total
Laurentian
Crude Oils
Product Oils
Laurentian Total
Maritimes
Crude Oils
Product Oils
Maritimes Total
Newfoundland
Crude Oils
Product Oils
Newfoundland Total
23.975
12.362
36.336
1.346
3.204
4.551
0.2589
1.0948
1.3537
0.1122
0.2225
0.3347
6.21E-02
1.49E-02
7.70E-02
2.68E-02
7.39E-03
3.41E-02
8.63E-03
0.00E+00
8.63E-03
7.170
4.959
12.129
0.403
1.285
1.688
0.0774
0.4392
0.5166
0.0336
0.0893
0.1228
1.86E-02
5.96E-03
2.455E-02
8.00E-03
2.96E-03
1.097E-02
2.58E-03
0.00E+00
2.581E-03
Total for Canada
72.320
10.750
11 per year
3.343
3 per year
0.771
0.142
0.064
0.012
one per year one in 7 years one in 16 years one in 86 years
Median Spill Size
<0 .5 Tonnes
< 2 Tonnes
2100 Tonnes 10,200 Tonnes 33,800 Tonnes 53,000 Tonnes
-32-
7. References
Anderson, C.M. and R.P. LaBelle. 1994. Comparative Occurrence Rates for Offshore Spills. Spill
Science & Technology Bulletin, Vol. 1, No. 2, pp 131-141. Elsevier Sciences Ltd., Oxford, U.K.
Anderson, C.M. and E.M. Lear. 1994. MMS Worldwide Tanker Spill Database: An Overview. U.S.
Department of the Interior, Minerals Management Service, Branch of Environmental Operations
and Analysis, OCS Report: MMS 94-0002.
CAC 1996. National Equipment Profile Study. Prepared by Consulting and Audit Canada (CAC) for the
Environmental Response Program, Canadian Coast Guard, Project No. 570-1019, March 1996.
Card, J.C., P.V. Ponce and W.D. Snider. 1975. Tankship Accidents and Resulting Oil Outflows, 19691973. Proceedings of the 1975 Conference on the Prevention and Control of Oil Pollution, San
Francisco, California, March 1975.
CCG 1991. 1991 Vessel Traffic Services (VTS) Update Study. Canadian Coast Guard, Ottawa, Ontario,
December 1991.
ITOPF 1999. The International Tanker Owners Pollution Federation Limited Oil Spill Database
Download from www.itopf.com
SL Ross. 1989. Expected Frequency of Spills from Tankers in or Near Canadian Waters. Prepared by
SL Ross Environmental Research Ltd. for the Canadian Department of the Environment and the
Canadian Coast Guard, August 1989.
SL Ross 1991. Estimation of Maximum Feasible Cleanup Capabilities for Large Tanker Spills in
Canadian Nearshore Waters. the Canadian Petroleum Products Institute, January 1991.
USCG 1994. Oil Spill Risk Assessment Model and the Ranking of Ports for Oil Spill Vulnerability. U.S.
Coast Guard R&D Center, Groton, Connecticut.