Fire broke out yesterday at a Beltsville industrial plant where potentially dangerous chemicals are used, but firefighters extinguished the fire several hours later with foam, Prince George's County officials said. No one was injured.

The fire erupted shortly after 3:30 p.m. at EG&G Pressure Science in the 11600 block of Old Baltimore Pike and was extinguished early today, according to Capt. Chauncey Bowers.

The firm manufactures seals, plates and coatings for the aerospace industry, he said.

Firefighters and hazardous-materials experts were concerned about the presence of chemicals in the building, including acids, cyanide and unspecified hazardous waste.

"It's the type of fire where you just can't make a mistake," Bowers said.

About 60 firefighters were on the scene last night, equipped with air tanks and dressed in masks and full-protection jumpsuits that covered them "like a safety envelope around their bodies," Bowers said.

After meeting with chemists from the company, firefighters used high-expansion foam to combat the fire because it is difficult to extinguish some chemicals with water, and the amount of water should be limited around the chemicals, Bowers said.

The foam was brought in last night from hazardous materials units in College Park, Annapolis and Kent Island.

Firefighters took their time in extinguishing the fire because of potentially lethal fumes and because exposure to the chemicals could cause severe burns, Bowers said.

A fire department official said no homes or other businesses were evacuated, because EG&G's one-story plant is in an industrial area, where businesses were closed for the holiday weekend.