A massive natural gas fire in Germantown late Tuesday night was caused by a "freak accident" in which lightning struck a gas transmission station, spewing flames 200 feet into the air, according to fire and gas company officials.

The fire, fed by a 30-inch-diameter gas pipeline, destroyed the Brink Gate transmission station on Waters Road off Rte. 355 and some surrounding woods, according to Capt. Ray Mulhall of the Montgomery County Fire Department.

Authorities closed nearby I-270 between Rtes. 121 and 118 for more than five hours after the 10 p.m. blaze, he said.

There were no injuries, and Washington Gas Light Co. officials estimated the damage at $500,000.

Both Mulhall and James T. Chido of Washington Gas Light called the incident highly unusual. "This is the first time in recent history that a gate station was hit by lightning," Chido said.

The station connects the underground lines of a Washington Gas Light Co. subsidiary with the pipeline of Columbia Gas Transmission Corp., which starts in Louisiana and runs through Maryland to Pennsylvania.

The Brink Gate Station is one of three transfer stations in Montgomery County between Washington Gas Light and Columbia Gas Transmission. Most stations are located away from population centers for safety reasons, officials said.

Washington Gas Light has 6,000 miles of pipeline running throughout the area, 60 miles of which is a major line 12 to 30 inches in diameter that transfers gas from one line to another. Lines that run into individual homes are usually three-quarters of an inch wide, Chido said.

In addition to Washington Gas Light, Columbia Gas Transmission, Consolidated and Transco companies have natural gas pipelines running through Maryland.

By law the lines must be buried at least three feet underground, Chido said. But the line comes out of the ground at gate stations. Lightning hit some equipment outside the door to the gate station and set off a chain reaction Tuesday night, burning the building and igniting the gas, Chido said.

Three or four times a year lightning hitting the earth sends electricity through the ground and causes ruptures in pipelines, which are usually not dangerous, Chido said.