A chocolate manufacturer, R.M. Palmer Company, failed to evacuate a Pennsylvania factory after some employees reported smelling gas before an explosion leveled part of the plant in March, killing seven workers, a federal official said this week.

“Seven workers will never return home because the R.M. Palmer Co. did not evacuate the facility after being told of a suspected gas leak,” Kevin T. Chambers, an area director with the Occupational Safety and Health Administration in Pennsylvania, said in a news release on Thursday.

“Ensuring the safety of a workplace is expected of employers and required by law,” he added. “The company could have prevented this horrific tragedy by following required safety procedures.”

In a statement on Friday, the company called his remarks “inflammatory, callous and irresponsible.”

“R.M. Palmer stands by its safety program and policies and has already contested the OSHA citations in this matter,” the company said. “The company disputes each of the citations and contends that the agency had no basis to issue these citations as stated.”

OSHA imposed $44,483 in penalties against R.M. Palmer for not evacuating the plant, not clearly marking emergency exit signs, improperly splicing cords and for several record-keeping violations.

The agency said it had been investigating reports that workers complained of a gas smell before the March 24 explosion at the plant in West Reading, Pa., a borough of about 4,500 residents roughly 65 miles northwest of Philadelphia.

The blast, which happened around 5 p.m., flattened a two-story factory building and damaged another.

Seven people were killed. Eleven others were injured and three families living in a nearby apartment were displaced, according to the National Transportation Safety Board, which is investigating the blast.

N.T.S.B. investigators determined that the explosion involved two gas leaks from service fittings to a gas line adjacent to the factory installed by UGI, a natural gas and utility company that serves Pennsylvania.

A representative for UGI could not be immediately reached on Saturday night.

In a statement days after the explosion, the company said, “We take our responsibility seriously, and we are working with local authorities and state and federal agencies to determine the cause of the incident.”

R.M. Palmer pointed to the N.T.S.B. findings from the ongoing investigation to rebut the OSHA citations, which the company said were “predicated upon a ‘leak’ inside of a Palmer building.”

A July N.T.S.B. investigation update, the company said, “contains no reference to any natural gas leak inside any Palmer building.”

“Until the N.T.S.B.’s investigation is complete, there is simply no basis to evaluate OSHA’s statement that an evacuation would have prevented the seven tragic deaths that occurred,” the statement continued.

Last month, the N.T.S.B. revealed that its investigation had hit a snag.

The agency announced it had subpoenaed the Pennsylvania Public Utilities Commission, which oversees UGI, and removed the state agency as an investigative partner after the commission failed to obtain and provide unredacted inspection and investigation reports from UGI.

R.M. Palmer, which was founded in 1948, is known for making seasonal chocolates, including Easter chocolate bunnies. It employs around 850 people, according to its website.

About 35 office staff members and 70 factory employees were inside the two buildings at the time of the blast, officials said.

The N.T.S.B. is expected to complete its investigation “likely sometime next year,” according to R.M. Palmer, which said it was continuing to cooperate with the inquiry.