DOVER, Del. (AP) — State environmental officials say a cleanup is underway after hundreds of gallons of a highly corrosive chemical spilled at a southern Delaware poultry processing plant.

Officials say the spill occurred about 11:45 a.m. Thursday at the Mountaire Farms plant in Selbyville. It involved about 318 gallons of peracetic acid, a chemical commonly used in the food industry as a disinfectant to guard against microbial contamination.

Mountaire released a statement saying four employees were evaluated and released from a local hospital after coming into contact with the chemical in a parking area.

Mountaire agreed last month to pay a $420,000 civil penalty and offer an alternative water supply to residents living near its Millsboro production facility, where high levels of nitrates from the plant's wastewater contaminated drinking water wells.