A smoldering fire at PSNH's main power plant in Bow yesterday morning drew dozens of firefighters from six surrounding communities.

The coal-fired plant had been shut down over the weekend for scheduled maintenance, according to Station Manager Harold Keyes. When workers tried to start it up, smoke billowed from a secondary steam pipe far from the main line that powers two massive turbines.

Emergency crews were originally called for an electrical fire about 8:30 a.m. When they arrived, they found lubricating oil had collected between piping and thick insulation meant to keep heat in.

Armed with breathing tanks and hand tools, firefighters were forced to remove sections of the insulation piece by piece. As each piece was removed, the oil became exposed to air, causing it to briefly go up in flames. Firefighters doused the flames with dry-chemical extinguishers, according to Bow fire Assistant Chief Dick Pistey.

Because of the incredible heat inside the cramped pipe room, Bow fire officials asked for a second alarm, bringing in help from Concord, Allenstown, Pembroke, Dunbarton and Hooksett. Hopkinton covered the Bow station. Henniker sent a truck to relieve firefighters and refill air tanks.

"Basically, it wasn't necessarily a large fire, but it was labor intensive, which is why the second alarm units were called in," Pistey said.

The scene was under control by about 9:35 a.m. Firefighters left at 10:30 a.m. and were back in service for other calls by noon.

Keyes said the plant was down throughout the morning as workers replaced 6 to 8 feet of insulation that is three layers thick. The area was re-insulated and restarted by 2 p.m., according to Keyes.

No homes or businesses lost power during the incident. Energy consumption is relatively light during this time of year, Keyes said, which is why the plant was down for maintenance. The plant usually runs yearround to supply 478 megawatts of power to 189,000 residential, commercial and industrial customers, according to the PSNH website.