Underwriter Laboratories

UL LLC

The UL Certification Mark
Type	Private, LLC
Predecessor	Underwriters Laboratories
Founded	1894; 123 years ago (1894)
Founder	William Henry Merrill
Area served	104 countries
Key people	Keith Williams (President and CEO)
Number of employees	12,000 (2013)
Website	www.ul.com

UL is an American safety consulting and certification company headquartered in Northbrook, Illinois. It maintains offices in 46 countries. Established in 1894 as the Underwriters' Electrical Bureau (a bureau of the National Board of Fire Underwriters), it was known throughout the 20th century as Underwriters Laboratories and participated in the safety analysis of many of that century's new technologies, most notably the public adoption of electricity and the drafting of safety standards for electrical devices and components.

UL provides safety-related certification, validation, testing, inspection, auditing, advising and training services to a wide range of clients, including manufacturers, retailers, policymakers, regulators, service companies, and consumers.

UL is one of several companies approved to perform safety testing by the US federal agency Occupational Safety and Health Administration (OSHA). OSHA maintains a list of approved testing laboratories, which are known as Nationally Recognized Testing Laboratories.

Underwriters Laboratories Inc. was founded in 1894 by William Henry Merrill. Early in his career as an electrical engineer in Boston, a 25-year-old Merrill was sent to investigate the World Fair’s Palace of Electricity. Upon seeing a growing potential in his field, Merrill stayed in Chicago to found Underwriters Laboratories.

Merrill soon went to work developing standards, launching tests, designing equipment and uncovering hazards. Aside from his work at UL, Merrill served as the National Fire Protection Association’s secretary-treasurer (1903–1909) and president (1910–1912) and was an active member of the Chicago Board and Union Committee. In 1916, Merrill became UL’s first president.

UL published its first standard, “Tin Clad Fire Doors”, in 1903. The following year, the UL Mark made its debut with the labeling of a fire extinguisher. In 1905, UL established a Label Service for certain product categories that require more frequent inspections. UL inspectors conducted the first factory inspections on labeled products at manufacturers’ facilities—a practice that remains a hallmark of UL’s testing and certification program.