Four people have been taken to hospital after inhaling unknown fumes at a recycling plant on Truman Lane.
St John Tauranga operations team manager Ross Clarke said the Transpacific AllBrite Industries staff members were taken to hospital as a precautions.
"They were concious and displaying minor symptoms such as diziness and sore eyes."
A fire service spokesperson said it appeared a staff member had opened a bottle he thought was water.
The minute he opened the bottle fumes have come out and the liquid was spread through a lot of rubbish, he said.
Fire fighters have yet to find the bottle or determine what the chemical was.
One person is being treated by emergency service staff after being overcome by fumes released in a chemical spill.
Fire and ambulance staff were called to Transpacific AllBrite Industries on Truman Lane, Te Maunga at 3.20pm.
Fire northern communications shift manager Nicole Bernard said five appliances were in attendance.
"We're responding to a chemical spill. One patient has been overcome with fumes. We're administering first aid and investigation what sort of chemical it is."