It was founded in 1866 and is the largest provider of equipment breakdown insurance and related inspection services in North America serving over five million commercial locations.

On July 24, 2019, A.M. Best Co. affirmed the ratings of the Hartford Steam Boiler group and its member companies.

[citation needed] Hartford Steam Boiler (U.S.) provides equipment breakdown coverage through a network of brokers and agents and also through other insurance companies who partner with HSB and who include equipment breakdown as part of their insurance products for commercial lines and personal lines customers.

In recent years, HSB has extended the product concept to the farm owners and homeowners markets.

Hartford Steam Boiler employs over 1,200 engineers, inspectors and technicians,[2] which account for approximately 50 percent of its total workforce.

The company was conceived at a time when catastrophic boiler explosions were common events, occurring about once every four days.

Up until the 1850s in the United States, a great deal of manufacturing was carried on by small plants located in rural areas.

The advent of steam power created a new industrial hazard – disastrous boiler explosions.

[4] In the fall of 1857, a group of young men interested in science and mechanics formed the Polytechnic Club of Hartford.

One of the founders of the Polytechnic Club was Jeremiah M. Allen, who would become president of The Hartford Steam Boiler Inspection and Insurance Company and the principal American figure to develop and apply the principle of combining boiler inspections with insurance.