California Air Resources Board

The California Health and Safety Code authorizes the California Air Resources Board (CARB) to adopt air pollution standards for sandblasting operations. Title 17 California Code of Regulations sections 92000 - 92530 require that all abrasive blasting be conducted within a permanent building with some specific exceptions. Exceptions allowing outdoor blasting exist when 1) steel or iron shot / grit (the definition of steel or iron shot / grit is provided in section 92000(m) of the regulation) is used exclusively, or 2) the blasting is conducted with CARB certified abrasive, wet, hydroblasting, or vacuum blasting techniques and the item blasted exceeds 8 feet in any dimension or is situated at its permanent location. The regulations apply a 20 percent opacity visible emission standard to all permissible outdoor blasting regardless of the abrasive or the blasting technique used.

Under the regulations, CARB is required to certify abrasives used for permissible dry outdoor blasting as complying with specific performance standards. The performance standards require that the abrasives shall not contain more than 1 percent by weight material passing a #70 U.S. standard sieve before blasting, and that after blasting, the abrasives shall not contain more than 1.8 percent by weight material 5 microns or smaller. As an alternative to the before-blasting requirements, the abrasive shall not produce visible emissions more than 20 percent opacity when blasted in accordance with a specified test method. Compliance with these certification requirements helps to reduce fine particulate matter emitted to the atmosphere during permissible dry outdoor blasting.

An abrasive which is sold by its producer or vendor during the certified period is certified for use until it is gone. It is not required that the abrasive be used only during the period for which it is certified.  An advisory on this issue is available.