Lung cancer risk of diesel-exposed workers reconfirmed, kudos to MSHA for addressing hazard 10 years ago

The Center for Public integrity's Jim Morris was the first to report that two long awaited cancer mortality studies of US workers exposed to diesel exhaust finds significantly elevated levels of lung cancer. Researchers with the National Cancer Institute (NCI) and CDC's National Institute for Occupational Safety and Health (NIOSH) proposed the studies two decades ago, going great lengths to address methodological limitations identified in previous epidemiological studies of diesel exhaust-exposed workers. The bottom line, and with now stronger evidence than ever, there should be no question that diesel exhaust is carcinogenic to humans.

Underground miners in the U.S. are some of the workers most heavily exposed to diesel exhaust. By 1998, there were already dozens of studies showing elevated risk of lung cancer in groups of exposed workers (e.g., here, here, here, here) and the Mine Act directs the agency to issue health standards based on the "best available evidence." For those reasons and because feasible controls were available to reduce miners' exposure to diesel exhaust, the Labor Department's Mine Safety and Health Administration (MSHA) proposed a rule to address this serious hazard. After public hearings and a comment period, MSHA staff worked to prepare the final rule to be published before the end of the Clinton Administration. The complication?

Members of Congress, including Senator Harry Reid, sent letters in June 2000 to Labor Secretary Alexis Herman urging her to delay issuing a final rule to protect miners from diesel particulate matter until the NIOSH/NCI epidemiological study was complete.

They wrote:

"you should issue your final rule after completion and review of the NIOSH study even though that may temporarily delay the final rule. ..." [emphasis added]

A nearly identical letter was sent by Wyoming Senator Michael Enzi. The Senators also reminded the Labor Secretary of language in the FY 2000 appropriations bill directing that MSHA's rulemaking on diesel be "informed" by the NIOSH/NCI study.

Then MSHA chief Davitt McAteer did not cave to the congressional pressure. He relied on the sound directive in the Mine Act to rely on the best evidence that is currently available. MSHA staff completed their work and a health standard to protect diesel-exposed underground miners was published in January 2001. Had McAteer and the Clinton Administration acquiesced to the calls for a "temporary delay," MSHA would just now be preparing a final rule. Without the rule, underground miners were exposed to levels of diesel particulate matter (measured in total carbon) that averaged 800 ug/m3 per shift, and under the rule the maximum allowable shift average is 160 ug/m3. Multiply those exposure levels by 10 years of delay, and you can practically count the excess lung cancer cases.

I was employed at MSHA during the time its diesel rule was being develop, and we knew that the NIOSH/NCI studies were just barely getting underway. There was no doubt that it would be several years (optimistically) before these epi studies would be complete. We also knew, as I wrote in "Weight of the Evidence or Wait for the Evidence?" that an industry coalition was already using all kinds of tricks to obstruct the conduct of the NIOSH/NCI studies. (And that shenanigans continued through last month when the industry coalition sent letters to major scientific journals warning them against publishing the studies.)

Kudos to former MSHA chief Davitt McAteer and individuals in the Clinton Administration for issuing a rule 10 years ago to address miners' exposure to diesel exhaust. The NIOSH/NCI studies reconfirm the risk to miners' health, and punctuate the benefit of the rule on the books.

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This saga would make a great novel, like Advise and Consent, and as the scibe who has documented much of this, you could retire on the proceeds -- but then again, its too unbelievable for a novel. Your summary is dead on, and Davitt deserves the credit you give him and more -- although you have politely left out the difficulties NIOSH's timidity and narrow research focus created for MSHA during the process (as it always does, given the legislative decision to agency from its research arm), and how close the rulemaking came to death in the waning hours of the Clinton Administration as the OSHA ergonomics standard (which Congress soon killed) was prioritized over everything else DOL was doing. I seem to recall that is what happened to a coal dust rule as well.... As the CPR has pointed out today, this could happen with this Administration too given the long list of important health actions that are stacked up. With respect to the diesel risk assessment by MSHA, specific kudos also go to Dep. Sec. Andrea Hricko, whose perseverance made it possible for MSHA to do its first-ever independent peer review, Jon Kogut who painstakingly compiled and evaluated all the risk evidence, and the legal teams (Steelworks and DOL) who successfully and completely defended MSHA's risk assessment in court. You, I, the rulemaking team, Rep. Miller's staff, and others worked hard and for far too many years in order to overcome a determined and foe of real science and worker health, not to mention internal skepticism and outright ignorance. I hope this story will encourage the staff and lawyers and political officials in DOL and the Administration to take the risks that need to be taken if the law is to have any meaning at all.

By Pete Galvin (not verified) on 05 Mar 2012 #permalink

Pete Galvin (the commenter directly above) is one of the unsung heroes of worker health and safety. He and a small band of brothers did the yeomen's work on the MSHA diesel rule.

Excellent post to a lenghty saga. The never-ending quest for workers health and safety right, employers just don't seem to care....still in this day and age.

The findings of the two NCI studies are now undergoing a detailed peer and scientific review of the methodology and the conclusions, which have been the subject of great question and controversy over the last decade.

The studies further fail to note the major changes that have taken place in diesel engines and equipment over time. Diesel engines and equipment that were the basis of these studies are in some cases over 50 years old. Like any other technology, diesel engines have changed dramatically over the course of the last half-century based on advancements in engineering and emissions control technology and new fuels.

Over the last 10 years, emissions from heavy-duty diesel trucks and buses have been reduced by 99 percent for nitrogen oxides (NOx) - an ozone precursor - and 98 percent for particulate emissions.

In addition, the new ultra-low sulfur diesel fuel that has been required since 2010 has reduced sulfur emissions by 97 percent â from 500 PM to 15 PM.

None of these advancements are considered in the two studies. Instead, the studies focus on older engines that havenât been manufactured for decades.

Was the Diesel Forum a claimant in the long-ran litigation throughout the 2000s on whether the introduction of a more rigorous standard to protect miners from diesel particulates should be proscribed? Certainly individual members of DF were involved in one of the various formulations Mining Awareness Resources Group or Methane Awareness Group or MARG Diesel Coalition but it is completely opaque as to how DF members were involved in litigation, in consultative rule-making, in congressional lobbying and yet can still argue that their legitimate concerns were not represented????? This is still a big issue so I hope you can produce some informative answers.

By Richard Harkinson (not verified) on 20 Dec 2013 #permalink