MONTPELIER, Vt. – A Vermont firefighters union on Friday demanded an investigation of FairPoint Communications two days after the phone company was blamed for a nearly two-hour outage of the 911 emergency calling system serving northern Vermont.

Wednesday’s outage left at least one Chittenden County resident with a medical emergency trying to call 911 10 times during a two-hour period before finally getting help through an alternate, seven-digit number, said Matt Vinci, a captain in the South Burlington Fire Department and president of Professional Fire Fighters of Vermont.

“When our dispatchers do not receive the emergency 911 calls due to an unacceptable failure of the E-911 system, the equipment, training and personnel that stand ready to protect and serve are unable to due to a failed system,” Vinci said. “This failure left our state and its first responders without its lifeline,” added Vinci, whose union represents about 280 firefighters in 12 fire departments around Vermont.

Vinci said he was barred by confidentiality rules from providing any more details about the medical emergency, including in which community it occurred. He said he did not know whether the patient had to be hospitalized, but did not believe the person had died.

Meanwhile, two state agencies said investigations were already under way after Wednesday’s outage with one saying FairPoint had agreed to adopt a protocol of bringing in officials from Vermont’s Enhanced 911 Board on a conference call whenever the company is working on parts of its network critical to the 911 system.

“We had no idea that they were going to be doing that work [on the system] on September 3,” said David Serra, director of the E-911 Board. In talks since then, “We’ve worked out a protocol with FairPoint where we will be notified ahead of time, and we will be present at least on a conference [call].”

That would have several eyes on the system at the same time, ready to raise an alarm if work on the system triggered any problems, he said. Wednesday’s outage has been attributed to human error in which “FairPoint pulled the wrong plug and they didn’t notify us,” Serra said.

The problem left a Burlington call aggregation center on the phone company’s network unable to receive 911 calls, relay them as usual to a redundant call aggregating center in Rutland and then instantly onto the state’s E-911 system.

Serra said the conference call protocol was in place before FairPoint took over the bulk of the land-line phone systems from Verizon Communications in Vermont, New Hampshire and Maine in late March. He acknowledged Friday that making sure FairPoint was aware of the protocol may have been overlooked.

“It’s definitely an affirmative step that we should have taken,” Serra said. “We should not have taken for granted that FairPoint would adopt whatever protocol we had. I’ll take some of the blame for this, if FairPoint didn’t realize they were supposed to call us.”

But he added that the requirement for communication about work on the phone system was spelled out in state rules affecting phone companies operating within Vermont.

He said, though, that he was pleased with FairPoint’s response since the outage.

“To err is human, and to admit it is huge and to me that company stepped right up to the plate and took ownership, and I really appreciate that from them.”

Vinci said it was fine with him that the E-911 Board would investigate the incident, but that the state agencies that should lead the way are the Department of Public Service and Public Service Board.

The department could request, and the Public Service Board could issue financial penalties or other sanctions against the company, said Stephen Wark, director of public and consumer affairs at the DPS. He said until an investigation is complete, likely next week, what if any sanctions might be pursued won’t be known.

“We’re starting at the beginning, and we’re not going to take anything for granted,” Wark said.

FairPoint spokeswoman Beth Fastiggi said the company wants to make sure such an outage is never repeated and was cooperating fully in the state investigations.