(CNN) -- The head of an embattled Connecticut power company defended his utility's response to a freak fall snowstorm that -- six days after it hit -- continues to leave hundreds of thousands without electricity.
As of Friday night, about 283,000 households who get service through Connecticut Light and Power remained in the dark. The utility, which at one point had 831,000 such outages, has promised to return power to 99% of its customers by Sunday night.
"I believe CL&P has done a very good job," Jeffrey Butler, utility president and CEO, said Friday evening. "This storm is of historic proportions... Have you ever seen an event like this?"
Butler made his remarks a day after Connecticut's attorney general called for regulators to investigate CL&P, the state's main electric utility, over its handling of the storm.
Attorney General George Jepsen filed the request with the state's Public Utilities Regulatory Authority, which is already investigating CL&P over its response to power outages during Tropical Storm Irene in September.
Eight people have died in Connecticut due to the storm, four of them from carbon monoxide poisoning, Gov. Dannel Malloy has said. He told reporters Friday that there have been a total of 322 carbon monoxide cases statewide.
While saying he "sure hopes" he can trust Connecticut Light and Power, Malloy acknowledged that there were definite problems that must be addressed before the winter storm season begins in earnest.
To this end, the governor announced Friday that Witt Associates -- a consulting firm led by former FEMA Director James Lee Witt -- will "do a review of Connecticut Light and Power and UI (the United Illuminating Company) in the wake of their performance." The review will be done at no expense to the state and be completed by December 1, before a different panel probing similar storm-related issues completes its own report.
"(We are) bringing in outside expertise to take an immediate look," Malloy said. "I can't wait for the two-storm commission to make recommendations because we have winter staring us in the face."
The governor, specifically, said one area of focus will likely be the amount of tree branches that threaten power lines, adding that residents may have to sacrifice foliage for safety and energy security.
"What we have learned ... is that we are a vulnerable state to different types of weather conditions -- wind and snow are clearly two of those," said Malloy. "And I think we can do better, in the long run, to prepare ourselves."
Eighty shelters were open around Connecticut on Friday night, in addition to 109 warming centers. The governor said that food and water had been delivered to residents of 82 towns, with more goods set to be delivered upon request.
Butler, the Connecticut utility chief, said that the effort to restore power is in full swing. While acknowledging there may be "opportunities" for improvement, he blamed the weather conditions -- including as much as 20 inches of heavy wet snow in spots -- as the primary reason for the prolonged outages.
"Everyone I talked to, they've never seen anything like this," said Butler, who came to Connecticut after 27 years at Pacific Gas and Electric Company. "The destruction of the trees was unbelievable."
He said that between 5,000 and 6,000 workers were on the job working to cut back trees and restore power, committed to the Sunday night goal.
The late October storm killed at least 22 people around the eastern United States.
That includes six deaths in Massachusetts, not including a seventh under investigation, said Peter William Judge, public information officer for the Massachusetts Emergency Management Agency, on Thursday.
In New Jersey, eight storm-related fatalities were tallied, including three people who burned to death in house fires, one person who died when a branch fell on him, another who died when a tree fell on him, and three people who died in motor vehicle accidents. A ninth death was under investigation.
President Barack Obama has signed emergency declarations for New Hampshire and Connecticut, clearing the way for federal aid to supplement state and local response efforts.