A fire department spokesman says a report came in mid-morning Sunday that two storage tanks containing highly corrosive hydrochloric acid were leaking.
The area around the site has been evacuated.
But police say the area is light industrial and few people were in the neighbourhood when the leak was reported.
No homes are reported to be under threat.
Fire officials say the spill has generated a light cloud of acid fumes, which is drifting northward away from the city.