Feb., 21 /LOCKPORT, New York -- Firefighters and environmental experts were cleaning up on Tuesday after extinguishing an early morning fire that set off several explosions at a plastics recycling plant in this town, 22 miles north of Buffalo. No one was reported injured.

The fire, which destroyed the building housing Micro Pulverizing Inc., was reported about 1:30 a.m. The heat touched off several explosions inside the building, including one that blew a wall into the street, knocking down electrical power lines.

Investigators did not immediately determine what had exploded but believe it may have been a propane-like gas. Firefighters also were concerned by a chemical used by the plant, hexamethylenetetramine, which can release toxic gases when burned, but authorities said surrounding neighborhood homes and parks were not exposed.

In July 1997 a similar fire and a later explosion destroyed 1/3 of the Micro Pulverizing Plant, forcing the evacuation of about 100 homes within a ½ mile radius and knocked out power to 178 residents. The evacuations of homes were prompted by the fear that 22 pallets of the chemical hexamethylenetetramine would become quickly heated and pose a deadly risk. Hexamethylenetetramine, when quickly heated, breaks down into a deadly poison that is absorbed through the skin. It also breaks down into formaldehyde gas, which is carcinogenic.