Two workers were killed in an explosion at a Beijing chemical plant late Sunday, witnesses and the local government said Monday.

The blast happened around midnight at a workshop of FRST Chemical Co. in Yongshun township of Tongzhou District, a manufacturing town in the eastern suburbs of Beijing.

"I heard a bang and saw the place was on fire," said a resident surnamed Lu, who lives close to the plant.

Lu said he saw two walls of the factory compound had collapsed, and windows were broken in buildings at least 20 meters from the site.

A Tongzhou district government spokesman confirmed two workers died in the accident, which happened at 11:42 p.m..

He said authorities had launched an investigation, but did not give details.

The fire was put out early Monday. Police have restricted access to the site.

FRST, based in Guangzhou, produces latex for industrial use.