UL (Underwriter Laboratories) is a preeminent safety organization headquartered in Northbrook, Illinois. It stands as one of the oldest agencies providing certification for products and environmental claims. It is crucial to differentiate between UL approval and certification. UL categorizes its certification into segments: listed, recognized, and classified. UL certifies products, systems, facilities, and processes in alignment with industry-specific standards.

UL certification is conferred upon manufacturers who produce products in compliance with UL standards. It grants manufacturers the authorization to affix the UL mark after conducting the requisite tests themselves. UL does not directly conduct product testing; rather, it oversees manufacturers to ensure tests are conducted rigorously, adhering to the prescribed procedures.