The Merced Fire Department and Cal Fire responded to an ammonia leak Wednesday in Merced.
The internal alarm system at White Oak Frozen Foods, 2525 Cooper Ave., detected the gaseous leak around 11:15 a.m., said Fire Chief Mike McLaughlin.
Firefighters evacuated the building of its roughly 50 to 75 employees, McLaughlin said. No injuries were reported.
The processing plant's alarm automatically shut down the system, which uses ammonia for refrigeration, McLaughlin said.
"It's a brand new system, and they're working now to break in the system," he said.
The Cal Fire hazardous materials team also responded, McLaughlin said, and used detection equipment to ensure the ammonia had dissipated before allowing workers back into the plant.
A Merced fire engine and a battalion chief responded to the leak. Cal Fire responded with the hazardous material team and a battalion chief.
Firefighters left the scene at about noon.
A similar event on a larger scale happened in December, when an ammonia leak at Atwater's Dole plant forced the evacuation of 175 employees.
A 4-inch pipe broke on a heat exchanger on the roof of the 7916 Bellevue Road facility when a pressure build up overwhelmed the safety system.
No one was injured during that incident, which drew a large public safety response.