The chemical leak that prompted evacuations in Orange County, Calif., on Friday occurred at a site belonging to GKN Aerospace, a manufacturing company based in the United Kingdom that produces jet engine parts, landing gear and other components for military and civilian aircraft.

About 16,000 people are employed at the company overall, including at least 540 at the location with the leak in Garden Grove, Calif., according to a 2024 news release. Its products are used in planes produced by Airbus, Boeing and Bombardier as well as the space industry.

The Garden Grove site, one of 32 manufacturing plants the company has across the world, is part of California’s robust aerospace and defense sector, which directly contributes $35 billion to the state’s annual economic output, according to one estimate.

Many of those businesses are based in Southern California. Northrop Grumman, Lockheed Martin, Boeing and RTX all have substantial operations in the region.

“It’s largely a legacy of the World War II and the Jet Age of the 50s and 60s,” said Richard Aboulafia, a managing director at AeroDynamic Advisory, an aerospace consulting firm. “It’s even a subplot of ‘Hail Caesar,’ one of the Coen brothers movies.”

The Garden Grove site was undergoing an expansion to create a new production line, set to be completed in January 2027. According to a city planning document, the site, which has been in operation since 2004, sits on about 15.5 acres.

At this facility, plane windows and military aircraft canopies are designed and tested, including some used in commercial jets like the Boeing 787 Dreamliner, the company’s website states.

In 2018, the company was sold to Melrose Industries, an investment firm that specializes in purchasing struggling businesses and turning them around. GKN Aerospace traces its roots back to the industrial revolution.

Records show the Garden Grove facility has undergone four inspections by the Occupational Safety and Health Administration since 2018. The company was fined $2,550 or less for unknown infractions that have since been fixed.

Industrial accidents, like the potential one at GKN Aerospace, have a destabilizing effect on the aerospace industry, whose supply chain is made up of specialized businesses with few competitors.

A fire last year tore through a Pennsylvania factory that was a significant source of specialized fasteners, nuts, bolts and other components used in aircraft and engines around the world.

“Everyone’s output is dependent upon bottlenecks not happening, and this could be one,” said Mr. Aboulafia.