MANCHESTER, N.H. --
Police and fire officials in Manchester blocked some roads and monitored the air after a hydrogen leak was reported on South Willow Street on Monday.
Officials said the leak's source was a 9,000-gallon hydrogen tank at the Osram Sylvania plant. Crews responded at about 8:30 a.m., and the leak was brought under control later Monday morning.
Firefighters and others keep their distance from the potentially explosive hydrogen leak. About 200 workers were evacuated from the area. Because hydrogen is highly flammable, anything that might cause a spark was turned off.
"There's no cell phone usage within 500 feet, no portable radios or anything like that," fire Chief James Burkush said.
Hydrogen is also less dense than air and rises, so air traffic was rerouted, along with traffic on the ground.
"We've asked for flight patterns to be changed, and that was done," Burkush said.
A water plume was kept going in case the gas had to be diverted from the building, but with no wind, it rose straight up, officials said.
A plume of water is ready to keep flammable hydrogen away from other buildings. "There's no hydrogen detected in the plant," said plant manager John Tremblay. "We're monitoring every five minutes to make sure it's OK."
The plant uses hydrogen in its glass manufacturing process.
"We use a lot of fire to heat up our glass and mold our glass, and that's what the hydrogen's used for," Tremblay said. "We use oxygen and hydrogen as part of our fires."
After an hour working with gas company Praxair, firefighters traced the leak to packing material around a valve on the tank. Burkush said the material had come loose because of the recent extreme cold.
Tremblay said this was the first incident of its kind at the plant, and Burkush said the plant has an excellent safety record.
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