Years ago, as a student of occupational health, I was taught to hold in high regard threshold limit values (TLVs) developed by the American Conference of Governmental Industrial Hygienists to protect workers.

The authors of my graduate school textbook on industrial hygiene exclaimed that “Threshold Limit Values are recognized throughout the world for their expertise and contributions to industrial hygiene.” Despite the premium placed on space in limited-edition texts such as that one, the authors incorporated the entire 38-page TLV Booklet, as it is informally called, which ACGIH published in 1994.

Indeed, OSHA included TLVs in a Hazard Communication Standard that it issued in 1983. Specifically, if a TLV existed on a substance, it was to be included in the Material Safety Data Sheet for the chemical. In addition, when the TLV changed, the MSDS had to be amended to reflect the change. MSHA, too, incorporated the 2001 TLVs into the HazCom rule it finalized several years ago. ACGIH levels also are adopted by some nations and provinces. They are used as reference values by some insurers, and have been used against companies in litigation.

AN ICON IN HEALTH AND SAFETY

ACGIH describes itself as a “scientific organization” whose volunteers are “dedicated to promoting health and safety within the workplace.” Its TLVs “represent a scientific opinion based on a review of existing peer-reviewed scientific literature by committees of experts in public health and related sciences.”

The impression, then, is one of scientists who are pre-screened for potential conflicts and well-versed in the literature. According to ACGIH, these experts come together periodically to debate and approve occupational exposure limits out of a dedication to workplace health and safety.

INDUSTRY ATTACKS ACGIH CREDIBILITY

That is why it comes as a shock to read a lawyers' brief of allegations against the organization by several industry plaintiffs including the National Mining Association. The coalition has sued ACGIH because it objects to TLVs and how they have been set for four substances, including three of importance to mining: copper, crystalline silica and diesel particulate matter.

In the brief, the plaintiffs state ACGIH publicizes that its TLVs are objective, factual, and crafted by individuals free of conflicts of interest and bias. According to the brief, ACGIH asserts that TLVs are based on a scientifically valid process that considers all relevant data. There is just one problem: the plaintiffs charge that, based on “undisputed testimony” in ACGIH documents and sworn testimony, none of these representations are true [my emphasis].

SOME STUDIES ARE CONTRADICTORY

Instead, the brief alleges that ACGIH TLVs are contradicted by both the available science and leading scientists. It also alleges: Votes are often cast by members who are uninformed of the underlying literature. Exposure limits are “routinely authored, drafted and adopted by individuals with significant conflicts of interest and bias who are without fundamental qualifications to create industrial hygiene exposure limits.” Altruism does not drive TLV development; rather TLVs are seen as “products” that ACGIH sells.

Filed in 2004, the case is being heard in a Georgia federal courtroom, and has been narrowed to a charge that ACGIH violated the state's deceptive trade practices act. The case should finally be decided this year.

My call to ACGIH was not returned, so I don't know that organization's side of the case. Certainly, it has one. However, unless convincingly refuted, what is said in the brief is damning to the organization's credibility. I'm not yet ready to set fire to my textbooks, but I have stocked up on matches and lighter fluid, just in case.

AUTHOR INFORMATION

James Sharpe holds a masters degree in environmental health sciences and is certified in the comprehensive practice of industrial hygiene. He has nearly 30 years experience in occupational and environmental health and safety. He can be reached at sharpemedia@verizon.net