Updated 10:00 AM
ROCHESTER (AP) -- Two Rochester police officers have been treated and released after being exposured to ammonia fumes that leaked at a milk processing plant.
Fire officials say a buildup of pressure occurred and ammonia leaked from a valve at the Upstate Farms Cooperative, Inc. plant around 4 a.m. Thursday.
A police spokesman says one of the officers reported seeing a cloud over the plant, which was evacuated while emergency crews closed nearby streets.
A family of six living across the street from the plant were treated at the scene. One was transported to a hospital, but condition information wasn't available.
None of the 25 to 30 employees inside the plant were injured.
An investigation has begun to determine how the ammonia cloud was released.
A message left with Upstate Farms wasn't immediately returned.
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