Work in environments with risks of
dangerous gases or oxygen deficiency
Safe and sound
– or hidden dangers!
A report on the risks of ill-health when working in fumigated containers
and confined cargo spaces
Contents
Introduction
3
Fumigation of containers
Regulations exist
4
Oxygen deficiency and toxic gases in cargo holds
Several fatal accidents
8
Regulations are not always followed What may the consequences be?
How to protect yourself
Which are the substances in question?
Inadequate testing
How are the gases formed?
How to protect yourself
4
5
5
6
7
8
8
9
9
Regulations of The Swedish Maritime Administration 10
Additional regulations
Swedish Work Environment Authority
Swedish Rescue Services Agency
11
11
11
Introduction
In a globalized world transports are continuously increasing. Products
and goods are being moved to an increasing extent and at a faster rate
from one continent to another.
Containers, packed and loaded one week in China, India or South
America, are by quick sea connection soon reaching a containerharbour, for example in Rotterdam or Helsingborg. Some of these
containers may have been fumigated in order to kill vermin or pests,
which otherwise could ruin the cargo.
Other kinds of goods are transported to a greater extent and for longer
distances than before, for example bulk cargo of wood chips, pulpwood and woodpulp pellets. During the transport, processes starting
in the cargo may cause oxygen deficiency and/or form toxic gases in
cargo holds and adjacent spaces.
Fumigated containers should not be a problem. Fumigation is a deliberate action taken and for many years there have been regulations
on how the handle such a container when its content of food, wood,
textiles etc, has been treated with, in many cases, very toxic substances. But the regulations on marking and ventilation are by no means
always followed. The rapid transports of today also result in poisonous
substances still remaining in high concentrations when the container
is opened, as the time for the substance to evaporate is shorter than
before.
Until now, there has been insufficient knowledge of the chemical and
microbiological processes taking place in bulk cargos during the journey. It has been known that the oxygen can be consumed, but the fact
that toxic gases may form, with far more dangerous effects, is new
knowledge.
For this reason, TYA, the Swedish Transport Worker’s Union and
Ports of Sweden together, by this report, seek to:
- draw attention to and increase knowledge about the problem,
- inform about the regulations on transports of this kind of cargo,
regulations that are not always followed,
- point out, to the authorities concerned, the need for supervision
and control of the compliance with the regulations.
Fumigants against
vermin
Personnel handling containers may be exposed to lethal
gases when opening a container.
About 15 percent of the 8
million containers handled in
the port of Rotterdam during
one year have been fumigated
against vermin. The marking
of fumigated containers is
often defective. In unmarked
but fumigated containers concentrations of toxic substances have been found that by far
exceed existing limits. Most of
these discoveries have been
made in containers carrying
food.
Toxic gases in ships
In cargo holds and adjacent
spaces on ships personnel
may be exposed to lethal
concentrations of toxic gases.
Risks are at hand when transporting wooden goods but also
bulk cargo, for example of fish
or corn. There may be a risk
of acute oxygen deficiency, as
well as of toxic gases forming
during the transport. The
combination is lethal!
Safe and sound – or hidden dangers!
3
Fumigation of containers
Goods transported in containers, whether fruits, other food or textiles,
must be protected against vermin and parasites during the voyage. An established method is to use different fumigants that kill vermin during the
transport. This method is used in the whole world, also when exporting
from Sweden.
As long as the regulations are followed about how to mark and handle
containers to get rid of the residual biocides, the method do not pose a
threat to the life and health of people opening the container afterwards.
Regulations exist
In the framework of regulations of dangerous goods, IMDG (shipping),
ADR (road) and RID (rail), there are rules for protection of persons who
may get into contact with a fumigated container.
A container that has been fumigated must be labelled with a warning sign
on the doors of entrance:
shortest 250 mm
Warning sign of fumigation
* Date and
time of the treatment
shortest 300 mm
• Containers being fumigated, i.e. that have not been ventilated before closing the doors, must have a warning sign informing about which fumigant has been used and the date and time of the treatment.
Documents of transport must accompany the container. They must show the date of fumigation, the name of the fumigant and the amount used, together with instructions on how to remove residual products.
• Fumigated containers that have been ventilated should me marked with the date of ventilation.
• When the fumigated goods have been unloaded the warning sings of
fumigation shall be removed.
4
Safe and sound – or hidden dangers!
Regulations are not always followed!
In practice, if the regulations are not followed, dock workers and other
personnel can not know if the container has been fumigated:
• In many places the containers are fumigated, whether it is necessary or not. There are reports of containers being filled with gas in an automa tic way, by persons who have neither knowledge of the contents of the
load, nor of the properties of the gas. Containers exclusively filled with
TV-sets have been fumigated, as well as containers loaded with
mattresses, clothes and food.
• Marking is often inadequate, or even non-existing. The Rotterdam- report, and many near-accidents in Swedish ports, resulting in nasty
symptoms like breathing difficulties and nausea, shows that
unmarked containers may have been fumigated and are dangerous to
open without special knowledge and special equipment. Personnel
opening a container of tins in Sweden, may totally unexpectedly
encounter levels of gas that are lethal.
Many containers
are unnecessarily
fumigated
Marking is often
inadequate
• Normally the gases used should evaporate after a certain amount of
time. But usually the time passing between loading and fumigating
the container and unloading it is shorter than the time needed for
evaporation. Gas cylinders intended for several weeks of transport
are loaded into containers that reach port after only a week at sea.
The gas development, hence, is at its peak when the containers arrive
to be opened.
Fumigants are overdosed in relation
to the time of
transport.
What may the consequences be?
In a port in Skåne a border inspection veterinarian inspected an unmarked
container carrying figs. The veterinarian did notice a strange scent and
consulted with the carrier. The container was put aside and a firm with
specialist knowledge was called in to inspect and ventilate the
container.
As a result, it was found that the container held very high levels
of phosphine, in the form of a dry powder, which in contact
with water or humidity form a gas. This very
poisonous gas is used for fumigation.
When the container was ventilated bags of dry
products, containing phosphorus, were found.
The bags were thrown into a puddle of water
to make the gas form. After that the residual
product could be handled as normal waste.
Veterinarian could
have lost his life!
?
Safe and sound – or hidden dangers!
5
The result of this incident could have been far worse. The veterinarian’s
life could have been in danger, had he not observed the risk in time.
All occupational groups that open fumigated containers are exposed to
similar risks.
There have been several accidents of personnel being
exposed to dangerous gases when opening fumigated but
unmarked containers.
The symptoms of the affected have been dizziness, nausea,
headache, tiredness, difficulties of concentration and disturbed balance control. However, there are few official reports
of incidents because the symptoms of exposure to gas are
often diffuse. Daily exposure of even low levels of gas may
lead to ill-health.
How to protect oneself
A systematic approach is necessary to protect
oneself against an unknown danger.
In various ports a safety guide is applied,
which if methodically followed, results in a
reasonable degree of security.
External control
of container
OMÄRKT
The purpose of the safety guide is to inspect
a container before starting to work inside
of it when stripping or stuffing. It has to be
secured that the container is free of gaseous
as well as solid foreign substances.
On suspicion of foreign substances the work must be stopped and
personnel with specialist training called in, regardless of if the
container is empty or loaded. An
indication of a fumigated container
may be that doors and air holes are
sellotaped. There may also be bags
or boxes left behind, from which
the fumigant has evaporated.
The container must be taken care
of in order to make it possible for
the personnel to resume their work, without
the use of personal protective equipment.
6
Marked
according to
IMDG/ADR/RID
Are there
accompanying
instructions?
yes
no
follow the
INSTRUcTIONs
open the
container
NO suspicion
of health
hazard
STUFF/STRIP
according
to work
instrucitons
suspicion
of health
hazard
stop the work!
cONTAct the
foreman/works
management.
Make a note of
the deviation.
Safe and sound – or hidden dangers!
Which are the substances in question?
The following poisons, among others, are used for fumigation
of containers:
Methyl Bromide
Methyl Bromide is prohibited to handle in Sweden but allowed in several
countries in Asia. It is toxic when inhaled. At low levels of concentration it may have
a narcotic effect. Inhalation may result in dizziness, nausea, headache and disturbed
balance control. The respiratory organs get irritated. High levels of concentration
affects the central nervous system and the poison gets lethal.
Phosphine (phosphorus hydrogen)
Phosphine may be lethal at low levels of concentration. Acute poisoning may seriously
damage several organs. Inhalation of the substance in low levels of concentration may
lead to pulmonary edema. The substance affects the respiratory organs and may, at
worst, cause asphyxiation.
Chloropicrin
Forms a gas, which among other things has been used as a war gas during the First World War. High acute poisonousness.
Sulphuryl Fluoride
Sulphuryl Fluoride is a colourless and odourless gas, which causes irritated breathing organs, a slow way of speaking and slow movements. Later symptoms are chest pains, nausea, vomits, involuntary defecation, breathing difficulties and an increased breathing rate (which might cause pulmonary edema), delayed powers of reaction and
weakness. The blood circulation may be affected.
Carbonyl Sulphide
Inhalation may affect the central nervous system and death can be caused by breathing arrest.
Hydrocyanic acid (prussic acid)
Colourless with a smell of bitter almond. Very toxic and traditionally used for elimination of bugs, rats and the like. Hydrocyanic acid is also known by the name of Zyklon B, which was used in German concentration camps during the Second World War. The gas is extremely toxic and inactivates cell-breathing. Death may occur within 3 minutes after inhalation.
Ethylene
An extremely flammable gas. Even small amounts of ethylene in the atmosphere might cause a fire or an explosion. The gas displaces the oxygen in the air and in confined spaces there is risk of asphyxiation or unconsciousness with no previous warning.
There is no odour.
Safe and sound – or hidden dangers!
7
Oxygen deficiency and toxic gases in cargo holds
Oxygen deficiency
and gases forming
in the cargo.
At sea transports of wooden goods there is a risk of oxygen deficiency
in the cargo hold as well as of toxic gases forming in the cargo. This may
also be the case when transporting other cargos of organic material, such
as corn or fish, or by oil-contaminated water on board.
Several fatal accidents
During the last three years (2005-2007) seven persons have died and
eight persons have been injured on ships in Swedish ports because of
oxygen deficiency and/or toxic gases that have formed in confined cargo
spaces. Five persons have died when handling wooden goods, pulpwood,
woodchips or woodpulp pellets. Two deaths occurred when crew members entered a cargo hold with decomposing fish. Two earlier fatal accidents have previously attracted attention internationally: 2002 in Rotterdam when unloading woodpulp pellets and 2003 in USA when unloading
timber. Globally, there are probably a great number of unrecorded cases.
One person died
and seven persons
were injured by oxygen deficiency
and carbon
monoxide poisoning.
Testing only the
level of oxygen is
not enough.
When personnel go down into the cargo hold to unload they may encounter a combination of oxygen deficiency and dangerous gases in the
staircase. This may also happen after unloading when the cargo hold is
to be cleaned.
Insufficient testing
In one of the accidents mentioned above, in November 2006 on the
cargo ship Saga Spray in the port of Helsingborg, one person was killed
and seven persons were injured. The ship was carrying woodpulp pellets.
Testing made on board immediately after the accident showed not only
an oxygen deficiency but also a high level of carbon monoxide. The
discovery was alarming news.
Even though the level of oxygen is tested to be far above alarming levels,
the atmosphere may contain lethal amounts of carbon monoxide. If only
the level of oxygen is tested there is a false impression of safety. But as
a matter of fact, the situation can lead to unconsciousness and death in
a few minutes. The carbon monoxide formed is deadly long before the
level of oxygen has decreased to a lethal one.
Some wooden goods also generate carbon dioxide in such concentrations that damaging levels form before the level of oxygen is
alarmingly low. Furthermore, hydrogen
sulphide may have formed. It is still
to be examined what the effects
are when these very injurious
substances combine.
?
8
Safe and sound – or hidden dangers!
How the gases form
Different effects may arise according to which wooden goods are being
transported.
• At transporting wooden goods that has not been dried, such as pulpwood (logs) and woodchips, the oxygen in the cargo hold is consumed in a microbiological process when carbon dioxide is
formed. In such an environment hydrogen sulphide may also form.
• At transporting woodpulp pellets a chemical process takes place,
which consumes oxygen and emits carbon monoxide.
Carbon dioxide, carbon monoxide and hydrogen sulphide are gases that
may have dangerous effects when inhaled. Carbon monoxide replaces the
oxygen in the blood and blocks out the capacity of the blood to absorb
oxygen. Hence, the consequence might be asphyxiation.
There are limits of the minimum level of oxygen allowed as well as of
the maximum level of the gases. But those limits are not valid if oxygen
deficiency and a presence of carbon dioxide or carbon monoxide exist at
the same time. The combination of effects makes the “toxicness” of both
phenomena much stronger. If an already low level of oxygen has reduced
the capacity of the blood to absorb oxygen, the effect is much worse if,
at the same time, there are gases present that also hamper the capacity of
the blood to absorb oxygen.
Limits do not take
into consideration
a combination of
effects!
How to protect oneself
Before allowing personnel to enter a cargo space it must be ventilated.
In larger spaces this is done automatically when the hatches are opened.
After the ship-crew has tested the level of oxygen in the atmosphere an
Entry Permit is given. It is then considered safe for the unloading personnel to enter. This was the case also on the ships where accidents or nearaccidents occurred. Evidently, the procedure is inadequate.
Except for breathing appartus there is no personal protective equipment
that gives protection against oxygen deficiency or carbon monoxide.
Therefore, it is of extra-ordinary importance to have strict routines of admittance to areas where there is a risk of oxygen deficiency or dangerous
gases.
Ventilate! Test
levels of gas and
oxygen …. also in
staircases!
Some areas need to be very carefully examined, for example staircases
where no automatic ventilation takes place when hatches are opened. The
atmosphere in such spaces is not always tested. The dangerous gases may
remain there as long as 20 hours.
Testing the level of oxygen may indicate an on-going process generating
carbon dioxide or carbon monoxide. But the lethal level of carbon monoxide in the atmosphere is difficult to read since it displaces a minor part
of the oxygen level. For this reason, the level of carbon monoxide, and
also hydrogen sulphide, should be tested separately.
Safe and sound – or hidden dangers!
9
Based on experience made in several Swedish ports the personnel of the
freighters is not always interested in, and sometimes even show a dislike
of, testing for dangerous gases.
26 hours of
ventilation may
be necessary before
admittance into a
cargo hold!
To read
Most important for the protection of personnel unloading wooden goods
from getting into contact with injurious gases is testing. A good rule is to
handle cargo holes on freighters transporting organical solid bulk cargo in
the same way as on a tanker. When it comes to tankers everybody is fully
aware of that nobody should enter the cargo holds until the atmosphere is
tested and declared clear of gas.
In the port of Helsingborg a strict programme of testing cargo holds and
adjacent passages is carried through, regardless of if the ships crew has
given its go-ahead or not. The employer in the port has to take all measures necessary to prevent personnel from ill-health or accidents.
Gases are not formed only during the voyage. Testing of the atmosphere
also has to be done when the hatches have been closed, for example because of rain.
The first scientific article on dangerous gases or oxygen deficiency in cargo holds: Hazardous OffGassing of Carbon Monoxide and Oxygen Depletion during Ocean Transportation of Wood Pellets
(Urban Svedberg, Jerker Samuelsson, Staffan Melin). Published in The Annals of Occupational
Hygiene (http://annhyg.oxfordjournals.org), doi:10.1093/annhyg/men013.
Regulations of The Swedish Maritime Administration
Regulations of The Swedish Maritime Administration (2008:4) on transport of cargo
were taken into effect 1 April 2008. They include provisions on how to supply information about the risks of bulk cargo and testing of the oxygen level and dangerous
gases. The rules are brought forward as a result of the accidents that have occurred.
• Information about cargo
If solid bulk cargo is not to be classified according to regulations of The Swedish
Maritime Administration on Packed Dangerous Goods (the IMDG Code) but has chemical properties that may pose a potential risk, information must be supplied about the chemical properties of the cargo.
• Analysis of the oxygen and detection of dangerous gases
When a ship transports solid bulk cargo, which may emit dangerous gases or cause oxygen deficiency in the cargo hold, there must be an instrument on board with the capacity to test the level of oxygen and to detect dangerous gases in the ship.
The instrument shall be brought together with detailed instructions for use.
Instruments on board a Swedish ship shall comply with the requisites in the regula-
tions of marine equipment of The Swedish Maritime Administration.
Crew members must be well informed about how to use the instrument.
General advice
Carbon monoxide, carbon dioxide and hydrogen sulphide are common gases, which may be dangerous and therefore shall be possible to test.
10
Safe and sound – or hidden dangers!
Further regulations
There are laws and other applicable regulations, not specifically aimed at
poisonous atmosphere in containers and cargo holds, that include rules to
protect people from getting injured.
Swedish Work Environment Authority
The statute book (AFS) of The Swedish Work Environment Authority
includes applicable rules to, among other things, judgement of
risks, information to personnel and demands for training when
handling risks.
• Systematic Work Environment Management (AFS 2001:1)
KEMISKA
ARBETS
MILJÖRI
SKER
• Chemical Hazards in Working Environment (AFS 2000:4)
BEKÄ
MPN
INGS
MED
EL
• Pesticides (AFS 1998:6)
• Use of Personal Protective Equipment (AFS 2001:3)
• Work in Confined Spaces (AFS 1993:3)
• Dock work (AFS 2001:9)
• Occupational exposure limit values and measures against
air contaminants (AFS 2005:17)
When it comes to work with fumigated containers and work in confined
spaces on ships the Swedish Work Environment Authority (in the latter
case together with The Maritime Safety Inspectorate) has published a
list of preventive measures, as a result of actual regulations by the
authorities.
AFS 200
0:4
AFS 19
98:6
AFS
1998
:6
AFS
1998
:6
AFS
1998
:6
Swedish Rescue Services Agency
There are laws on protection against accidents, including amendments to
regulations and instructions (for further information: www.srv.se).
Work shall be planned and arranged
in such a way that it can be carried out in
healthy and safe surroundings.
The Swedish Work Environment Act,
Chapter 2, §2.
Safe and sound – or hidden dangers!
11
Unmarked containers should always be handled as
working environment risks, if you suspect that they have been fumigated.
There must be instructions on how to open them and
how to equip the personnel with protective devices. Respiratory protective
equipment with combination protection, full protective clothing
and access to cleanser and water are appropriate means.
Before entering cargo holds and adjacent spaces on bulk ships
the atmosphere must be tested with reference to the level of oxygen and, in
applicable situations, carbon monoxide, hydrogen sulphide, carbon dioxide
and lowest inflammable temperature.
There is no protective equipment in the world
against such threats – except breathing apparatus.
HAMN
STUVERI
SKOLAN
Box 1826, 171 26 Solna, tfn 08-734 52 00, fax 08-734 52 02.
E-post: [email protected] Hemsida: tya.se
bildinfo.se, Art No. 72 037-H, 1:2, 1000 ex, 2009.01
The course of an accident is very fast,
much faster than you can imagine!