The Importance of Evaluating Diesel Particulate Exposures – The Soot Carries the Carcinogens
Diesel exhaust is made up of gases, vapors and solids (soot). The solid elements of diesel exhaust are collectively referred to as diesel particulate matter (DPM). Diesel particulate matter houses some of the most dangerous carcinogens like polycyclic aromatic hydrocarbons, cadmium, chromium, benzene and arsenic. Elemental carbon constitutes around 40% of the diesel particulate mass which is why it is a good marker for diesel particulate exposure. The ultra-fine particles that make up diesel particulates can be inhaled, transferring the carcinogens into the lungs and starting the disease process. The carcinogens carried on the soot can also be absorbed through the skin and even ingested. It’s no surprise that many of the cancers associated with diesel exhaust include organs like the lungs, bladder, kidneys, throat, stomach and colon, all of which are involved in processing the inhalation or ingestion of substances.
It’s vital that air quality sampling evaluate diesel particulates because exposure to elevated diesel particulates essentially means your cancer risk is elevated. Corporations like railroads know this fact and so when they perform air quality testing, they almost always test for gases like nitrogen oxides. Railroads don’t want to test for diesel particulates because if their testing shows elevated levels of diesel particulates, they have a hard time arguing that their employees’ cancers are not work-related.
Many workers suffer regular diesel exhaust exposures, including: miners, construction workers, heavy equipment operators, bridge and tunnel workers, railroad workers, oil and gas workers, loading dock workers, truck drivers, material handling operators, farmworkers, long-shoring workers, and auto, truck and bus maintenance garage workers. There are literally millions of workers in the United States who suffer chronic diesel exhaust exposures, highlighting the importance of properly controlling the exposure level.
Are Permissible Exposure Limits Common?
The recently implemented PEL in the EU allows workers to earn a safer living, however, the PEL is not common in most countries. Currently, there is a PEL regarding diesel particulates for miners in the United States, but OSHA has not passed a PEL for diesel particulates in general occupational settings. Exposure limits for diesel particulates have been proposed in the United States but likely thanks to some powerful political lobbies (railroads, petrochemical conglomerates, trucking manufacturers et al.), those limits have not been codified to law. The limit in the EU will serve as a precedent for more PELs to be set in other countries, including the United States.