As part of the new OSHA silica rule, employees who may breath in silica dust should be tested to determine their exposure. Employees whose exposures are above the Action Level of 25 micrograms per cubic meter (ug/mg) and/or Permissible Exposure Limit of 50 ug/m3 are subject to the provisions of the new standard. Testing must follow OSHA or National Institute of Occupational Safety & Health methods. During testing employees wear a high flow pump connected to a PVC filter cassette. Air passes through a cyclone device before entering the cassette. The samples must be sent to an American Industrial Hygiene Association approved laboratory for analysis.