UL history

In late 1903, a fire ripped through the Iroquois Theatre, killing over 600 people — mainly women and children — in the first eight minutes alone.

To address these issues, UL’s Reexamination Service was created in 1904.

In 1905, UL established a Label Service for certain product categories that require more frequent inspections.

In one anecdote that has been handed down through generations of UL employees, two fire extinguisher manufacturers met outside of UL’s headquarters sometime in 1906.

In 1907, Merrill wrote that UL was planning on extending its Label Service to hoses, watchmen’s time detectors, fire doors, insulating joints and other fittings used in fire protection.

William Henry Merrill Jr. | Popular Electricity, November 1911

In 1912, he is appointed to oversee UL’s New York office.

Over the years, Small assumes a variety of roles and responsibilities within the organization and, by 1916, is promoted to vice president in charge of overseeing the New York office.

Like UL president Curtis Welborn, Brandon defers his university education so that he can serve as Second Lieutenant in the United States Army during World War I. Brandon is a 1919 graduate of Mississippi A & M College where he receives a Bachelor of Science degree in Electrical Engineering.

Henry Clay Eddy retires as UL’s president and becomes Chairman of its Board of Directors – a position he holds until 1921.

Once the inspector determines that the door has been safely constructed, the door receives a label bearing the name "Underwriters’ Laboratories." At right, an engineer tests a fire extinguisher. | Symbol of Safety, 1923

UL’s success in this approach sets the stage leading up to the introduction and passage of the federal Air Commerce Act in 1926, which eventually leads to the establishment of the Federal Aviation Administration (FAA).

Since 1928, DEMKO has evaluated products for safety at its full-service laboratory in Herlev, a suburb of the Danish capital, Copenhagen.

Merwin Brandon retires and H. Baron Whitaker is elected president of UL. Whitaker is a 1936 graduate of North Carolina State College.

In 1946, he begins his career at UL as an assistant engineer in the Gases and Oils Department.

In 1952, UL purchased 153 acres of property in Northbrook, Illinois, located about 25 miles north of downtown Chicago.

Jack Bono retires and Tom Castino becomes president of UL. In 1960, Castino graduates from University of Illinois at Urbana-Champaign with a degree in Mechanical Engineering and immediately finds employment in UL’s Fire Protection department.

In fact, it wasn’t until 1968 that the United States government began requiring the installation of seat belts in all cars.

In 1979, the organization moved its headquarters to a 153-acre campus in Northbrook, Illinois, 25 miles north of its former downtown Chicago location.

It also creates a new joint venture with China Certification and Inspection Group (CCIC). Knoblauch retires in 2004.

On January 1, 2012, Underwriters Laboratories transformed from a non-profit organization to a for-profit company in the United States A new subsidiary named simply UL LLC, a limited liability corporation, took over Underwriters Laboratories’ product testing and certification business.

In 2018, UL certifies the first drone to meet this standard.

UL is celebrating its 125th anniversary in 2019.

UL’s Start Safe Playbook, released in May 2020, pairs UL’s collective expertise with guidance from leading health organizations.