The National Institute for Occupational Safety and Health, under the authorization of the Federal Mine Safety and Health Act of 1977 and the Occupational Safety and Health Act of 1970, provides a testing approval and certification program assuring commercial availability of safe personal protective devices and reliable industrial hazard measuring instruments. NIOSH develops improved performance regulations, tests and certifies (or approves) devices, and purchases approved and certified products on the open market to verify quality of manufacture. The Certified Equipment List (CEL), a database of all certified respirators and coal mine dust personal sampler units, may be accessed on-line, or it may be downloaded. The on-line, searchable database is updated monthly. The downloadable CEL is updated semi-annually, as of March 31 and September 30.