The firm, also known as New England Confectionery Company, was cited by the US Department of Labor's Occupational Safety and Health Administration (OSHA) for the violations at its Revere production plant.
The proposed fines relate to the release of 8,000 pounds of ammonia from the refrigeration system on 5 October 2012 and the violations must be abated by 17 May 2013.
The firm manufactures Necco Wafers, Canada Mints, Candy House Candy Buttons, Mary Jane, Slap Stix, Sky Bar and Sweethearts.
Inspections by OSHA's Andover Area Office on 15 and 23 October identified shortfalls in the process safety management program under which the firm must analyze, address and minimize potentially catastrophic hazards associated with using large amounts of ammonia in its refrigeration system.
Necco failed to develop safe operating procedures for the refrigeration system; did not adequately inspect or have adequate preventive maintenance procedures for machinery, piping and storage vessels used in the refrigeration system, said OSHA.
The agency added that the firm did not update procedures and inform workers of changes to the refrigeration process, its equipment and management.
"This was a serious and preventable incident that could have resulted in the loss of human life," said Jeffrey Erskine, OSHA's area director for Middlesex and Essex counties.
"The fact that none of the plant's workers were injured does not relieve this employer of its responsibility to establish and maintain a complete, effective and fully functioning program to anticipate, analyze, identify and correct problems, so that an ammonia release doesn't occur in the first place."
The site lacked an emergency response plan for employees who responded to the ammonia release, workers were not trained to use fire extinguishers and an unsuitable motor was used in a hazardous area where combustible dust was present, reported OSHA.
Necco has 15 business days from receipt of its citations and penalties to comply, meet with OSHA's area director or contest the findings before the Occupational Safety and Health Review Commission.