OSHA does not certify or approve any products. Any claim that a product is “OSHA approved” is misleading.
Product standards determine performance requirements, and certification indicates conformity to standards. How those products are installed and used in the workplace falls under OSHA.
OSHA standards and regulations may mandate the use of a product that meets a standard, but not specify how that product is certified. For example, the OSHA PPE standards require that hard hats, safety glasses and safety footwear meet specific ANSI standards; the OSHA respirator standard requires that products be NIOSH approved. OSHA officials often participate in the development of those standards, and ANSI and OSHA work in close cooperation.
For some products, such as electrical products in the workplace, OSHA requires third-party approval. When this is the case, it specifies the standards to which the products must be approved, and accredits test labs to certify to those standards. These labs are designated Nationally Recognized Testing Laboratories, or NRTLs. Keep in mind, however, that OSHA does not require third-party approval for PPE. Therefore no lab – even if it is an NRTL – should claim to be recognized by OSHA to test and approve PPE.