The company at the center of Friday’s fatal water line break in Boston’s South End has a lengthy history of troubling safety violations, including citations for workers lacking oxygen underground and for conditions that could lead to cave-ins, federal records show.

Atlantic Drain Service Co. of Roslindale, which advertises as one of Boston’s “most successful and respected drain cleaning companies,” faces tens of thousands of dollars of unpaid fines for violations reaching back to at least 2012, according to Occupational Safety and Health Administration records and an agency spokesman.

Three city officials briefed on the investigation into Friday’s accident on Dartmouth Street confirmed Atlantic Drain was the firm performing work in the trench, which filled with water when a pipe ruptured, trapping two laborers.

The company was cited as recently as March for failing to provide a rescue team — a crew specifically trained to rescue workers in underground spaces — for two employees working in a tunnel on Tremont Street, less than three blocks from Friday’s accident, the OSHA records show.

The records do not indicate whether those two workers were injured. But the government documents show it was the second time in less than a year that Atlantic Drain failed to provide sufficient rescue teams. The company had been cited in August 2015 for lack of rescue teams at another Tremont Street worksite, the records show.
 

A woman who answered the phone Friday at the company’s Roslindale office declined to comment. No one answered the door at the firm’s office.

The company’s website identifies it as a family-owned company in business for nearly 40 years.

“We have the manpower and equipment to take care of any drain our commercial & residential customers can dish out,” the website says. “From household pipes to hotel main lines, if there’s a problem we will fix it!”

But the company has been cited for a litany of serious safety problems.

Federal regulators issued nearly $74,000 in fines against the company in 2012 for four repeated safety infractions and one “willful” violation — the most severe penalty imposed — for problems uncovered at a Harrison Avenue worksite in Boston, records show.

“An employee was exposed to cave-in hazards while working in a 9.1-foot-deep trench that had straight-cut walls with no cave-in protection,” according to the records for that “willful” citation.

“A willful violation is a deliberate violation on the part of the employer,” said Ted Fitzgerald, an OSHA spokesman.

“It means the employer had knowledge, and the inspection determined a particular safeguard is required, and for whatever reason, the employer chose not to provide it,” Fitzgerald said.

The repeated violations from the 2012 case included lack of employee training in recognizing and avoiding hazards. OSHA records indicate Atlantic Drain has not paid the $74,000 fine. An agency spokesman said Friday afternoon that fine has been sent by the federal government to a debt collector.

Atlantic faced fines for similar problems in 2007, the records show. News reports from that time indicate the company was repairing a sewer line for a hotel at Boylston and Charles streets. OSHA officials inspected the site after receiving reports that employees were working in a 12-foot-deep trench that allegedly lacked any protection against cave-ins.

The more recent violations, from March, include eight citations, with six categorized as serious and two found to be repeat infractions, the records show.

In the March citations, Atlantic failed to ensure employees had enough oxygen while working underground and neglected to provide any air monitoring to “assess employee exposure to hydrogen sulfide and other toxic gases likely to be present due to leaking sewer lines,” the records said.

The company was also penalized for failing to train employees “in the recognition and avoidance of tunnel hazards, such as personal protective equipment, air monitoring for respiratory hazards, ventilation and emergency procedures.”

Atlantic Drain faced nearly $22,000 in fines for the March violations, which remain unpaid, the records show.