Firefighters are investigating a hazardous material incident at the Mitchell Resource Management Centre.
A drum buried beneath a rubbish pile is believed to contain hydrochloric acid.
Staff members noticed a chemical reaction was occurring with other metals in the rubbish pile and rang Emergency Triple Zero (000) at 1:51pm.
Twelve cars were evacuated from the centre, which will now be closed for several hours. There is no threat to surrounding areas.
Firefighters are digging through the rubbish pile to identify the source.
The area will then be tested and made safe before patrons are allowed to return.
The Hazardous Materials Unit, Breathing Apparatus Van along with two pumpers and a commander are on scene.