Policy
Briefing
IARC Study, including
development of the Monograph
September 2014
Background
IARC, the International Agency for Research into Cancer, has had an interest in bitumen since
about 1987 and intended then to classify the material as carcinogenic. However, there was
insufficient evidence to support the theory at that time and the "monograph" since then has
carried the classification 3, which indicates no firm evidence of harm to humans. In 1998 IARC
decided to carry out a survey of asphalt workers in Europe who had died of lung cancer in the
past 20 years or so, to see whether the relative mortality index (RMI) was higher than in the
population as a whole. The survey was conducted in 7 EU countries, plus Israel, and indicated
that there was a slightly higher RMI than normal, but the results were inconclusive, showing in
more than one country that asphalt workers were actually healthier than those in other
industries; further, that there were "confounders" in the results which rendered them
unreliable. For example, the relatives of those who had died were not asked whether the
workers had smoked all their lives, or had had lifestyles that would have encouraged a disease
such as lung cancer. IARC had to conclude, therefore, that it needed to do a second phase
study to rule out the "confounders". That study is now complete and has indicated that there is
no link between bitumen fumes (in the road construction context) and lung cancer.
The final step is the production of the new “Monograph” by a separate cell of IARC. This was
finally published in late October 2011 and bitumen fumes when encountered during paving
operations were categorised as 2B – “possibly carcinogenic to humans” – which is the same
category as, for example, mobile phones and coffee! This slightly higher classification than
expected was due to some late results of tests carried out in the United States, which indicated
that there might have been some “mutagenic” issues, albeit the temperature of the bitumens
used was higher than experienced during paving operations. It is likely, therefore, that some
further research into what exactly this means in the long term may be required and to be
underwritten by the European asphalt industry (together with our American colleagues).
Potential impact on members
The immediate and medium term implication for the British asphalt industry is hard to
ascertain precisely at this moment, not least because the UK HSE has not commented or made
any ruling yet on the Monograph result. The IARC final report, which is critical in this respect,
is not expected for many months – possibly as many as 24 months – and it is probable that HSE
will not seek to impose any restrictions on the industry until it has seem this final report. Even
then, Category 2B has not imposed any restrictions on the use of either coffee or mobile phones
and it could therefore be speculated that the new category will not have any impact on asphalt
paving operations.
Policy
Briefing
The European proposal, however, is to follow the American example and to move quickly to
lower the temperature of the production and laying of asphalt by changing to Warm Mix Asphalt
as standard. This has many positive effects: it hugely reduces the generation of all fumes and
thus minimises any health effects from bitumen fumes; it extends the laying season; it is better
for compaction and thus the quality of the road; and a road can be closed for less time, as it
can be reused for traffic almost immediately after the laying/repair operation has finished.
One surprising by-product is the ability to use a higher proportion of Reclaimed Asphalt
Pavement (RAP) in the mix.
MPA’s position
MPA has been supportive of the work being undertaken in Europe and has played a leading role
within EAPA and with colleagues across the Atlantic (who have the same concerns as we do).
We accept that Category 2B is the most realistic that the asphalt industry could (with hindsight)
have expected and that it should have no adverse restrictions imposed on it as a result. We will
now work with European and American colleagues to better understand what is meant by
“mutagenic” issues and to do whatever is necessary to ensure that the use of asphalt as a
paving material is not affected in the future.
MPA’s activity programme
At present MPA is waiting to see what the reactions of the industry bodies on both sides of the
Atlantic are and to support whatever action is deemed appropriate to minimise any future
implications of the IARC result.
Contact with other bodies
At present there is no dedicated contact programme with the UK Government, but strong links
are being maintained within EAPA and Eurobitume and also with the US asphalt trade
association, NAPA.
Further information
Please contact Simon van der Byl, Executive Director MPA, Public Policy, and Secretary General
EAPA
Committee reference
Asphalt Committee