Firefighters are working to contain an unidentified powdered chemical found in an Ashburton farm shed where a number of animals are dead.
The Fire Service were called to a Cochranes Rd rural property about 8.30am.
Shift manager Karl Patterson said there was a chemical spill from a "very old container", and the residents believed it was behind the death of several pigs and a cat.
"The situation was that there was a number of pigs that came in contact with the chemical in the last day," he said.
"The residents believe they have died as a result, and there was also a dead cat this morning. That was trigger point and that's when we got involved.
"That's obviously still to be confirmed, but that's their assumption."
Patterson said there was five fire trucks and a Hazardous Substances Unit from Timaru at the property.
"They are working to contain those chemicals and there are also carrying out precautionary decontamination with two members of the public."
He said no one has been evacuated yet, but the incident was being taken seriously.