BREWER, Maine -&nbspThe New Hampshire company that installed a new heating system that apparently caused carbon monoxide poisonings at an apartment complex and sent at least eight people to the hospital, did not have the required permit, a city official said Tuesday.

Two women who got sick as a result of the odorless gas leak remained hospitalized Tuesday, one in serious condition, and are expected to stay longer, according to a relative of one of the women.

“There was not a permit issued” for the new propane furnace at the River House apartments on Penobscot Street, Dave Russell, Brewer code enforcement officer, said Tuesday. He said a city permit is required anytime a new heating system is installed or a heating system is changed or modified.

“Right now, both the state Oil, Solid Fuel, Natural Gas and Propane [board] inspector is looking into it as well as the state fire [marshal’ s] inspector,” Russell said.

It’ s not clear whether the technicians working for Concord Gas of Bow, N.H., were licensed to work in Maine. The property is owned by EWT LLC of Concord.

Doug Dunbar, assistant to the commissioner of the Department of Professional and Financial Regulation, said Tuesday that if an out-of-state company is hired to do an in-state job, “technicians are required to be licensed in Maine.”

Dunbar said he couldn’ t talk about the issue of whether the company’ s employees had proper licenses because the case is under investigation.

Concord Gas officials and Keystone Management Co. Inc. of Orono, which oversees the property, did not immediately return calls on Tuesday.

A separated vent pipe leaked carbon monoxide into the 31-unit apartment complex, sending Lisa Ouellette, 43, to St. Joseph Hospital on Sunday and seven others on Monday.

Ouellette, whose apartment is located near where the separated pipe was releasing the poisonous gas, was found unconscious by her boyfriend Sunday afternoon. It wasn’ t until Monday when others in the apartment complex grew sick from the accumulating odorless gas that the Fire Department was called. Because some residents were at work, only 21 people were evacuated.

Three of the seven people who were hospitalized Monday were staying in Ouellette’ s apartment. Brewer Fire Department crews evacuated the building around 11 a.m. Monday, after Ouellette’ s niece Kristina MacKenzie, who is a nurse, recognized the signs of carbon monoxide poisoning and called 911.

“All seven were treated for CO poisoning,” Bethany McKnight, St. Joseph Hospital spokeswoman, said Tuesday. “Three were treated in our [hyperbaric] chambers” on Monday and released that evening.

McKnight said it is very rare that the hospital’ s two hyperbaric chambers, which can provide a supersaturated oxygen environment, are used for carbon monoxide poisonings.

“The last time we had these numbers was during the ice storm [of 1998],” she said, adding that people at that time were using “untraditional heating sources” to keep warm.

Three of Ouellette’ s relatives and a friend drove down from Millinocket on Sunday after hearing of her illness. All four stayed at Ouellette’ s apartment that night with MacKenzie, who was already staying over.

All five women said they had headaches and felt dizzy Monday morning, but initially attributed the problem to being tired. It wasn’ t until later in the morning, after two of the women had gone to the hospital to check on Ouellette’ s condition, that MacKenzie recognized the symptoms she and the two women remaining at the apartment were experiencing.

Ouellette remained in critical condition on Tuesday, and her friend Joan Fisher, 55, of Millinocket, who came to town Sunday evening, was being treated on the cardiac floor, Sheila MacKenzie, Ouellette’ s sister and Kristina MacKenzie’ s mother, said Tuesday.

“My sister is doing a little better,” Sheila MacKenzie said. “She’ ll probably stay in critical care for another day and if her test results come back good, she’ ll be moved to a regular floor.”

Fisher, who was unconscious when firefighters arrived to evacuate the apartments Monday, “is having some cardiac problems, so she’ s staying” another night, MacKenzie said.

MacKenzie’ s other sister, Mary Ouellette, 48, and daughter, Kristina, 24, also were taken to the hospital for treatment. Both are now doing fine, she said.

Carbon monoxide poisoning is believed to have starved Lisa Ouellette’ s body of oxygen. The gas has a cumulative effect and can cause brain damage and death with lengthy exposure.

“We won’ t know if there is any permanent effect until down the road,” MacKenzie said. “It might take awhile. It’ s very dangerous.”