HAVERHILL — For a few minutes yesterday, there were many anxious people at the Pentucket Medical Associates building just north of downtown.
Patients and staff members were rushed to exits because of a leak in a container of gas used to treat people with lung problems.
A tank of the gas developed a leak, forcing the evacuation of staff members and patients. Fire officials said five people who may have been exposed to the gas were evaluated by Trinity EMS ambulance personnel at the scene, while one person was taken to Merrimack Valley Hospital for evaluation.
Around 1 p.m., staff members in the medical facility heard a hissing sound coming from a lab on the second floor. They called the company that owns the tank and dialed 911, according to Deputy Fire Chief Eric Tarpy and Pentucket Medical spokesman Bill Plante.
The Fire Department ordered the building evacuated while firefighters investigated the leak. Tarpy said no new patients were allowed to enter the building until it was declared safe. Workers and patients were allowed back inside after about 40 minutes.
The room is self-venting, so when gas was released it was vented from the room to the outside of the building, officials said.
“As much as it was an emergency, the way the room was designed handled the problem,” Tarpy said.
No one was injured, but a couple of staff members were checked to see if they had an ill effects as a result of exposure to the gas mixture, Plante said. He said the gas leaked out of a cracked regulator on top of the tank.
Tarpy said the gas is harmless in small amounts, but could be harmful in large doses.