Low-toxicity dusts: current exposure guidelines are not sufficiently protective.

Exposure to low-toxicity dusts, which have previously been viewed as 'nuisance dusts', can cause chronic obstructive pulmonary disease or other nonmalignant respiratory disease. In Britain, the 'de facto' airborne exposure limits for these dusts have remained unchanged for >30 years; currently, they are 10mg m(-3) for inhalable dust and 4mg m(-3) for respirable dust. During this time, exposures in industry have decreased and although in the past, many occupational dust exposures may have exceeded these limits, today this is less likely. However, there is good evidence from epidemiology and toxicology studies that current dust exposures may still present a risk to workers and that for some of those who are affected, there are devastating health consequences. Numerous researchers and others have drawn attention to the necessity to control dust exposures to levels lower than are currently accepted in Britain. It is proposed that until regulators agree on the safe occupational exposure limits for low-toxicity dusts, health and safety professionals should consider 1mg m(-3) of respirable dusts as a more appropriate guideline than the value of 4mg m(-3) currently used in Britain.