The wood dust issue in review.

Editor's note: This is the second of a two-part series on wood dust. Published in October, part one focused on the report by the International Agency for Research on Cancer which concluded that there is "sufficient evidence" linking wood dust with a rare form of nasal cancer. Part two begins with a look back at the Occupational Safety & Health Administration's 20-year effort to establish a federal rule limiting employee exposure to wood dust.

Setting the stage: What the unions wanted, what industry got

In 1971, OSHA began regulating wood dust as a "nuisance dust," which established limits of 15 mg/[m.sup.3] for total dust and 5 mg/[m.sup.3] for respirable dust. Since then, numerous efforts have been made to create a specific standard to limit worker exposure to wood dust.

In the mid-1980s, the American Conference of Governmental and Industrial Hygienists (ACGIH), a scientific advisory group, recommended OSHA set a threshold limit of 1 mg/[m.sup.3] for hardwoods and 5 mg/[m.sup.3] for softwoods. The workers unions demanded even stricter limits - 1 mg/[m.sup.3] across the board for both softwoods and hardwoods. Neither succeeded.

The Inter-Industry Wood Dust Coordinating Committee, a coalition of more than 20 trade associations, convinced OSHA that permissible exposure limits of 5 mg/[m.sup.3] for both softwoods as well as hardwoods (with 2.5 mg/[m.sup.3] for western red cedar) was not only safe for workers, but economically feasible to achieve as well.

On Sept. 1, 1989, wood dust became one of more than 400 chemicals specified by OSHA in its revision of permissible exposure levels under the Air Contaminates Rule. But within 10 days of OSHA's publishing of the Air Contaminates Rule, the blanket rule was contested by more than 28 unions. The United Brotherhood of Carpenters and Joiners not only protested the fact that OSHA set a wood dust exposure limit of 5 mg/[m.sup.3] vs. the 1 mg/[m.sup.3] it had hoped to have set, but the union also argued that wood dust's potential as a cancer-causing agent should have induced OSHA to put it under its own separate ruling.

Wood dust reversal

Following an appeal of the Air Contaminates Rule, the 11th Circuit Court of Appeals in Atlanta vacated the rule. Wood dust returned to being regulated by federal OSHA as a nuisance dust, with a limit of 15 mg/[m.sup.3], although many state's including Michigan, Minnesota, California, Washington, New Mexico, Alaska, Tennessee, Virginia, Vermont and Connecticut continue to use the stricter limits. Oregon and Hawaii enforce a 10 mg/[m.sup.3] limit while the remaining states enforce 1971 limits of 15 mg/[m.sup.3] for total dust and 5 mg/[m.sup.3] for respirable dust.

IARC links cancer and wood dust

Lending support to previous claims by unions on the hazards of wood dust, the International Agency for Research on Cancer announced late last year that there is "sufficient evidence" to classify wood dust as a Group 1 (proven) human carcinogen. Breathing wood dust, IARC claims, can lead to a higher risk of a rare type of adenocarcinoma involving the nasal and paranasal sinuses.

In presenting its findings in Vol. 62 of the Monographs, IARC cited more than 350 studies to support its claim. The agency focused on three stages of woodworking: rough milling, component making and assembly. Targeted operations included sawing/milling, planing, chipping, sanding, routing, shaping, tenoning, moulding and jointing. Sanding was considered to be of the most concern because it almost exclusively produces fine dust particles.

The IARC classification of wood dust automatically activates a change in Material Safety and Data Sheet labeling, which falls under OSHA's Hazardous Communications Standard. Caution labels and MSDS must now incorporate a cancer warning. In addition, workers need to be educated on the possible effects of wood dust exposure.

As early as May of 1995, in a memo to members of the National Particleboard Assn., Executive Director Rich Margosian cited possible scenarios for wood dust in the future:

* OSHA could institute reform legislation that would reinstate all or many of the original 428 substances covered in the 1989 Air Contaminates Rule.

* OSHA could pursue a specific rule-making for wood dust.

* OSHA could include wood dust in a generic PEL rulemaking. "There is already a substantial data base available supporting a 5 mg/[m.sup.3] PEL, but given the new IARC status of wood dust as a Group 1 carcinogen, industry could anticipate a push to lower levels," Margosian said.

Industry and unions debate IARC report

Should the IARC study be viewed as the last word on wood dust's potential health risks? No, says Dr. John Festa, chairman of the II-WDCC, in the exclusive point-counterpoint that begins on page 86.

"IARC relied primarily on studies done in Europe, under working conditions that do not appear to be representative of modern workplace conditions in the U.S. The species of wood, the process in the workplace, the presence of other workplace chemicals and the work practices in modern U.S. workplaces likely differ considerably from the situations covered by the studies IARC reviewed (particularly compared to the pre-World War II era covered by many of the studies)," says Festa.

"There is no riskless void..." counters Sheldon Samuels, senior advisor for Policy and Research for the United Brotherhood of Carpenters and Joiners. "Thus, no level of exposure should be called 'safe,' a word that means, to most, 'no risk.'"

Added Samuels, "The current finding was made necessary by accumulating world-wide data from perhaps 100 peer-reviewed reports, published in peer-reviewed professional journals.... The finding has very high credence."