FAIRFIELD - Fairfield police say they're investigating an overnight hazmat situation on Commerce Drive.

Fire officials say they were called to MCP Metal Specialties at around 12:15 a.m. due to an unusual odor in the area. Witnesses say the powerful smell was accompanied by a hazy dust cloud.

According to firefighters, the vapor cloud was coming from one of the plant's chimneys. They say a malfunctioning machine over-pressurized and began leaking Gallium trichloride, which is a chemical used in LED lighting.

The company says it's confident any chemical leak was contained to the building and is joining the town in an investigation into what caused the malfunction.

Officials say one firefighter was sent to the hospital as a precaution.

VIDEO: Fairfield hazmat situation