Firefighters expect a blaze burning at Niagara Lubricants on Chandler Street to continue for hours as they wait for petroleum products in the building to burn off.
"Right now, it's going to be a long time before this goes out," Division Chief Don McFeely said shortly before 3 p.m. "It's got a lot of product in it,and we can't hit it from where we are."
Fourteen to 15 propane tanks in the building have exploded periodically, emitting a large boom and sending new flames into the air.
Smoke was pouring from all sides of the three-story brick building that occupies about an acre when firefighters arrived at about 5:50 a.m.
More than five hours later, vats of oil and other materials continued to catch on fire, sending plumes of black smoke into the sky.
At about 12:50 p.m. there was another explosion and flames began to burst out of the top floor of the building.