- The name "Welsbach" came from Dr. Carl Auer von Welsbach (1858 to 1929) of Austria. He invented the incandescent mantle which was used in early gas lighting.
- Welsbach has been in operations as an entity since 1877.
- In 1896, the Welsbach Street Lighting Company of America installed gas lamps with the first mantles used in this country, in Freehold, NJ.
- From 1896 through 1940, the Welsbach Company, formerly a United Gas Improvement (UGI) subsidiary, manufactured incandescant gas mantles.
- The Welsbach Street lighting Company also manufactured the original gas lamps found in Riverton, NJ.
- In 1971, The Jamaica Water Supply company acquired Welsbach. By 1974, they merged, adopting Welsbach as part of its name.
- In 1995, the firm reorganized as EMCOR Group. Inc.