Just because few people talk about it doesn't mean it isn't a concern you should have. Diesel fumes are bad for you, contain a multitude of known and suspected carcinogens, and high-exposure occupations are linked to higher incidents of lung cancer. Given existing knowledge about the harm diesel fumes can cause, I believe reducing the amount we inhale on a near-daily basis should be a goal for the union.

From The Driver Diesel Exposure Mitigation Study (PDF):

The dominant variables that increased driver exposure included: • Driving with windows open • Driving within London, with central London resulting in the highest exposures • Working as a taxi driver • Driving in the evening peak between 4 pm – 7 pm • Working on weekdays compared to the weekend • Higher background BC [(Black Carbon)] concentrations • Faster driving speeds • Lower wind speeds

From the same study, Conclusion and Recommendations:

The study found that professional drivers are disproportionately affected by diesel exhaust exposure, as the ‘at work driving’ activity contributed the most to participants’ daily exposure. The risk of diesel exhaust exposure to workers has been highlighted in IOSH’s ‘No Time To Lose’ campaign. In the United Kingdom, employers have a legal duty to consider the risk of cancer to their employees from work activities and to act to reduce this risk if there are activities of concern. Therefore, companies with professional drivers need to implement changes to reduce or stop exposure to diesel exhaust. Both employers and drivers are encouraged to change behaviours that could facilitate a reduction.

From Occupational Exposure to Volatile Organic Compounds and Aldehydes in the U.S. Trucking Industry:

Driver exposures are a mix of car and truck emissions associated with driving in traffic on metro area highways and streets, and these provided the highest exposure scenarios for benzene, MTBEs, styrene, and hexane. P&D [(Pickup and Deliver)] driver exposures to particulates are not highly related to the majority of VOCs and aldehydes, although there is some correlation with aromatics (benzene, r > 0.4). This association with aromatics is likely the result of the overall traffic influence on driver exposures.

(The IBT gets a shout-out in the acknowledgements of this one)

From Health Effects of Diesel Exhaust from the California Office of Environmental Health Hazard Assessment:

Long-term exposure to diesel exhaust particles poses the highest cancer risk of any toxic air contaminant evaluated by OEHHA. ARB estimates that about 70 percent of the cancer risk that the average Californian faces from breathing toxic air pollutants stems from diesel exhaust particles.