what is NRTL approval
OSHA, an agency of the Department of Labor, publishes a list of Nationally Recognized Testing Laboratories. Organizations currently recognized by OSHA as NRTLs: 1  Canadian Standards Association (CSA) (also known as CSA International). 2  Communication Certification Laboratory, Inc. (CCL).he testing and certification are done to U.S. consensus-based product safety test standards. These test standards are not developed or issued by OSHA, but are issued by U.S. standards organizations, such as the American National Standards Institute (ANSI).