A landmark lawsuit that some speculated could have spelled the end of the world's most widely used occupational exposure limits and bankrupt the sponsoring organization was settled out of court last week.
Companies that mine and process trona, a mineral used to make baking soda, animal feed and soda ash, a key ingredient in glass, had sued the American Conference of Governmental Industrial Hygienists (ACGIH), which in 1999 proposed a Threshold Limit Value for trona dust of .5 mg/m3 of respirable dust. The companies argued that trona has no long-term health effects, that the nuisance dust TLV is protective, and that the trona TLV is scientifically unfounded.