Amazon requires platform online sales merchants to make a test report / certificate for the product to prove that the product meets the relevant standards and the product is safe. The laboratory issuing the modified test report / certificate must be an NRTL accredited laboratory.
NRTL stands for Nationally Recognized Laboratory, which is the abbreviation of English Nationally Recognized Testing Laboratory. The Occupational Safety and Health Administration (OSHA) under the U.S. Department of Labor requires that products used in the workplace must be tested and certified by a nationally recognized laboratory Ensure the personal safety of users.
Screenshots of Amazon's official website accredited laboratory