KEENE, N.H. (CBS) — Gov. Maggie Hassan said she will ask the Public Utilities Commission to open an investigation after gas leaks left four people hospitalized and sent the Keene Fire Department on over a hundred separate carbon monoxide-related calls this weekend.

“I urge all residents in the area to continue to stay vigilant and watch for signs of exposure, and if they suspect any issues, to shut off gas appliances and heating systems, evacuate to safety, and call 911,” said Gov. Hassan in a statement Sunday. “I also urge all Granite Staters to invest in carbon monoxide detectors as they can save lives in situations like this.”

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One of the four people hospitalized was a woman who was found unconscious in the utility room of a Hallmark store. Officials said at least two people also went to the emergency room on their own after experiencing similar symptoms. All four have been treated and released.

A Liberty Utilities van in Keene, New Hampshire on Saturday night. (WBZ-TV)

A Liberty Utilities van in Keene, New Hampshire on Saturday night. (WBZ-TV)

Liberty Utilities said a power problem at their propane production plant in Keene led to operational issues Saturday morning that affected the mixture of propane and air flowing into the distribution system. In a statement, the company said that the change caused gas with high Btu content to enter their system–and that the high Btu gas could “potentially produce carbon monoxide at the gas appliance/burner tip in a home or business.”

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By the time Keene Fire Department’s response operations were finished around 2 a.m. Sunday, they had responded to 114 related calls. The department said that, during a 10-hour period of their response, they and other companies their responded to about 1,200 buildings in Keene–all of which were cleared of any carbon monoxide hazards. They received help in the form of 75 Fire/EMS units provided by other fire companies in Massachusetts, Vermont, and New Hampshire.

Keene firefighters responded to numerous calls for gas leaks on Saturday. (WBZ-TV)

Keene firefighters responded to numerous calls for gas leaks on Saturday. (WBZ-TV)

The State Emergency Operations Center was activated. The American Red Cross opened a warming center at the Keene Recreation Center on Washington Street at 6:30 p.m, which was shut down at 11 p.m.

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Liberty Utilities provides services to 89,000 natural gas and 44,000 electric distribution customers in New Hampshire. The company is advising anyone who experiences dizziness or headaches to immediately get fresh air and call 911 if they suspect elevated carbon monoxide levels or gas odors inside their business or home.