Exhaust from diesel engines is “carcinogenic to humans”. Experts meeting at the WHO International Centre for Cancer Research (the CIRC) in Lyon to assess the dangers of diesel exhaust have in fact raised its toxicity level. Diesel exhaust has been reclassified from group 2A to group 1 in the WHO (World Health Organisation) classification, alongside cadmium and plutonium.
In 1988, diesel exhaust was included in the group of substances deemed “probably carcinogenic in humans” (group 2A). The same year, petrol exhaust was included in the group of substances that were “possibly carcinogenic to humans” (group 2B).
In moving diesel exhaust into the WHO’s top – and most dangerous – group, these experts “based their decision on sufficient evidence linking exposure to diesel exhaust to an increased risk of developing lung cancer”. They also discovered a “positive link with an increased risk of bladder cancer”, the CIRC adds. Petrol exhaust, however, remains in group 2B.
Reducing public exposure
The principal study leading to these decisions was published in March 2012 by the American National Cancer Institute. According to their conclusions, significant exposure to diesel exhaust increased the risk of death from lung cancer in underground miners in the United States.
“However, we have learned with other carcinogens such as radon, that initial studies carried out on workers were often confirmed among the population as a whole”, points out Dr Kurt Straif, head of the CIRC monographs programme. “Which is why action to reduce exposure should take not only workers into account but the rest of the population too”, he stresses.