A toxic chemical leak at a North Carolina meat processing plant injured eight people and forced thousands of workers out of the facility.

An ammonia spill at the Smithfield Packing plant in Tar Heel occurred Tuesday morning.

A company spokesman says a water heater tank collapsed and severed an ammonia line, spilling some 30,000 gallons of the cleaning fluid.

Authorities closed down about five miles of highway near the plant as Hazmat teams responded to the leak.

An investigation is underway.