Traffic was snarled on Chain Bridge Road in northeastern Fairfax County for more than an hour yesterday after construction workers broke through a natural gas line and authorities closed the road until the line could be repaired.

The incident was one of a number of problems involving natural gas leaks in Fairfax County over the past two days, county fire officials said. No injuries were reported.

According to fire authorities, a two-inch gas line leading to a single-family house in the 600 block of Chain Bridge Road was broken by construction workers at about 8 a.m. The house was evacuated and several blocks of the road closed off until the line was capped at 9:45 a.m.

Two other gas line breaks were reported in Fairfax yesterday morning, both of which were repaired without mishap, fire officials said. At about 9:30, construction workers broke a half-inch gas line in the 6400 block of Anders Terrace in Annandale. Half an hour later, a three-quarter-inch line in Colvin Run Mill Park in Great Falls was ruptured when workers on bulldozers apparently struck it.

Fire officials also reported receiving more than 180 calls complaining of natural gas leaks in the Herndon area Wednesday. Investigation of all the reports turned up no gas leaks, officials said, and investigators concluded that an excess of an odorant called mercaptin in the gas had prompted the calls.