What are the health and safety allowable limits for exposure to respirable crystalline silica (RCS)?

The permissible exposure limits to respirable crystalline silica (RCS) also differ according to the country or the regulatory agency. In the UK, the Workplace Exposure Limit (WEL) which is laid down by the Health and Safety Executive (HSE) is 0. 1mg/m3 for an 8 hour time weighted average (TWA). The Occupational Safety and Health Administration (OSHA) in the United States has put the Permissible Exposure Limit (PEL) at 50 µg/m3 for an 8 hour TWA. These limits are to ensure that the health impact such as silicosis and lung cancer are prevented. Therefore, it is important that the air quality is checked and proper measures to control are put in place to ensure that the law is adhered to.