SCITUATE - Boston Firefighter Paul Cahill, who reportedly had a blood-alcohol level three times the legal limit when he was killed on the job, reported for work an hour before the fatal fire. Alcoholism experts say there was no way someone should have missed the fact that he was intoxicated.

Boston Firefighter Paul Cahill, who reportedly had a blood-alcohol level three times the legal limit when he was killed on the job, reported for work an hour before the fatal fire. Alcoholism experts say there was no way someone should have missed the fact that he was intoxicated.

Dr. Michael Randon, medical director at the Brockton Addiction Treatment Center and the Women’s Addiction Treatment Center in New Bedford, came to this conclusion:

‘‘He either drank on the job or he came to work so smashed I don’t know how they let him put his uniform on.’’

Boston Firefighter Warren Payne, who also died in the fire in August, had trace amounts of cocaine in his system, according to published reports.

The state Registry of Motor Vehicles confirmed yesterday that Cahill’s driving record showed he was convicted last year of driving under the influence after a July 2005 stop in Marshfield. The Boston Fire Department said it had no record of the alcohol-related conviction.

Cahill’s license was suspended for 180 days after he refused a breath test, and for 45 additional days after his January 2006 conviction. Ann Dufresne, a spokeswoman for the Registry of Motor Vehicles, said Cahill was required to participate in an alcohol education program as a result.

The revelation comes on top of reports of toxicology tests showing Cahill had a blood-alcohol level of 0.27 percent when he died fighting a restaurant fire in West Roxbury in August.

The autopsy information had Boston Mayor Thomas Menino calling on Thursday for ‘‘a stem-to-stern’’ look at the city fire department’s practices.

Steven MacDonald, a spokesman for the Boston Fire Department, said he was unaware of Cahill’s drunken-driving record. He said Cahill should have reported it to the personnel department, but the spokesman was unable to determine Thursday whether that had been done.

Also on Thursday, department spokesman Scott Salman released new details about Cahill’s activities on the night of Aug. 29, the date of the fire.

He said Cahill showed up about two hours late for a 14-hour shift that would have begun at 6 p.m. Cahill had arranged for another firefighter to cover until he arrived.

The fire started at about 9 p.m. Cahill and Payne, among the first to rush inside the building, died after the kitchen roof fell. The collapse resulted in a massive fireball.

At the time, department officials said firefighters ‘‘became trapped ... and disoriented’’ because of heavy smoke in the restaurant. Firefighters thought they were dealing with a routine kitchen fire until a buildup of gases in the ceiling sparked the inferno.

Salman said firefighters do not have to check in with a commanding officer or attend roll call at the start of their shifts. If a firefighter was inebriated, others in the station might not notice, he said.

‘‘If you’re crawling, that’s a little obvious, but if you’re sneaky or discrete, you can duck,’’ he said. ‘‘You could go to work and not open your mouth ... and as long as you’re not bouncing off the walls, you wouldn’t raise suspicions.’’

Salman said investigators reporting to the board of inquiry set up after the fire would have questioned other firefighters who may have seen Cahill in the station.

But Randon said that if Cahill’s blood-alcohol level was 0.27, he finds it hard to believe nobody noticed.

‘‘Anyone working with him would have picked up on it,’’ he said. ‘‘The thinking process is distorted. Physically, he’s not as adept... Someone driving with that level - he’d be a ticking time bomb.’’

A study done at the University of California at Davis showed that it would take eight to 10 alcoholic drinks to elevate a person’s blood-alcohol level to between 0.20 and .0.30. That degree of impairment can cause passing out, inability to walk, crying, rage, double vision and poor judgment, according to the study.

Randon said false-positive results are unlikely when blood alcohol is tested, but they can occur when drug testing is done. For example, he said, some dentists and doctors use cocaine as a local anesthetic, which might lead to readings of ‘‘trace amounts’’ in someone’s system.

Patriot Ledger reporter Robert Sears contributed to this report. Jennifer Mann may be reached at jmann@ledger.com .