NFPAhttp://www.nfpa.org/
The National Fire Protection Association. A consensus standards-making organization authoring several rescue-related standards including NFPA 1006 “Technical Rescue Personnel Professional Qualifications,” NFPA 1670 “Standard on Operations and Training for Technical Search & Rescue Incidents,” NFPA 1983 “Standard on Fire Service Life Safety Rope and System Components” and NFPA 350 “Guide for Safe Confined Space Entry and Work.”

OSHAhttp://www.osha.gov/
The Occupational Safety and Health Administration. A governmental entity responsible for developing federal regulations relating to safety and health issues. OSHA’s 29 CFR 1910.146 is the basis for procedures relating to Permit-required confined spaces in US, federally regulated facilities. This website allows free access to all OSHA regulations, pre-ambles, compliance directives, and letters of interpretation.

NIOSHhttp://www.cdc.gov/niosh/homepage.html
The National Institute for Occupational Safety and Health (NIOSH) is the Federal agency responsible for conducting research and making recommendations for the prevention of work-related disease and injury. The Institute is part of the Centers for Disease Control and Prevention (CDC) and provided much of the statistical analysis used in developmental stages of the Permit-required Confined Space standard.