After more than 40 years, a new rule governing federal standards for silica exposure may soon take effect. Silica, a type of sand commonly used in industrial manufacturing and the oil and gas industry, has been regulated by the federal government since the 1970s.  Currently, the general industry standard is 100 micrograms of silica per cubic meter; up to 250 micrograms are permitted at construction sites and shipyards.  New standards proposed by the Occupational Health and Safety Administration would lower the acceptable limit to 50 micrograms per cubic meter of air.

The new limit would be a marked change.  The new regulations may be complete by February 2016.