EVERETT — A contract worker who was injured in a Nov. 13 accident on Boeing’s Paine Field flight line died Sunday.

The mechanic, Ken Otto, was an employee of Everett-based Jamco America. He and an employee of a different contractor were working on a first-class seat in a 777 when a “partially disassembled” airbag system accidentally discharged, Boeing said in a statement released Monday.

Otto, 50, was taken by helicopter to Harborview Medical Center in Seattle. He died Sunday in Seattle.

The other worker, an employee of Vartan Product Support, was treated on site, taken to a local hospital and released, according to Boeing.

Both Jamco and Vartan are based in Everett and are subsidiaries of foreign companies.

Boeing declined to identify the worker, and a receptionist at Jamco America said the company does “not have any public information at this time.” But a person familiar with the accident confirmed Otto’s identity. His hometown couldn’t be confirmed late Monday.

Vartan did not respond to a request for comment.

Following the accident, “Boeing has reminded employees and suppliers, as well as airplane operators, not to make an electrical connection to the seatbelt airbag system unless all the components of the system are completely installed,” according to the company’s statement.

The state Department of Labor and Industries, Boeing and Jamco are investigating the accident.

Airbags are installed in thousands of airplane seats to meet federal safety requirements that passengers be able to withstand an impact equal to 16 times the force of gravity. Airbags are needed on “difficult-to-certify seat placements,” such as unconventional seats in first and business classes and bulkhead-row seats, according to AmSafe, a Phoenix, Arizona-based manufacturer of the devices.

The company has the only seatbelt airbags certified for commercial airplanes, according to AmSafe’s website.

Otto was working on an AmSafe device when the accident occurred. The company could not be reached for comment.

A Boeing spokesman said he was not aware of any incident similar to the Nov. 13 accident.

Outside suppliers make seats for Boeing airplanes. Customers purchase the seats from the suppliers, who deliver them to Boeing factories, where they are installed by Boeing mechanics.

Contractors often deal with problems identified by customers after a seat is installed, according to Boeing workers.

Two accidents on Boeing’s Everett flight line in 2012 also sent workers to Harborview with serious injuries. In one, a Boeing mechanic was crushed while working on a 747. In the other accident, a Boeing employee’s legs were crushed under a 787 that was being towed.

In the past five years, Labor and Industries has found violations in eight workplace safety investigations at Boeing’s Everett plant. The department found violations during two investigations into Jamco. It has not investigated any issues at Vartan Product Support.

Dan Catchpole: 425-339-3454; dcatchpole@heraldnet.com; Twitter: @dcatchpole.