1. U.S. Chemical Safety and Hazard Identification Board 2006
2. National Fire Protection Association 2016
3. OSHA https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=DIRECTIVES&p_id=3830 2016
4. OSHA https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FEDERAL_REGISTER&p_id=21152 2016