That's the opinion of OSHA's area office in Braintree, which investigated the Jan. 14 accident. The office fined Advanced Pipe Inspection Inc. of Boston $45,500 for 13 alleged serious violations of standards. The company was hired by the Massachusetts Water Resources Authority to clean clogged overflow pipes in the plant's sewage digesters.

"OSHA standards are designed to protect workers from the hazards of working in confined spaces, " said OSHA Area Director Brenda Gordon. "These standards must be strictly followed to avoid accidents."

OSHA's citations chiefly address deficiencies in the safeguards taken for working in overflow boxes that provide access to the pipes. The overflow boxes contained unsafe levels of flammable gas. According to OSHA, Advanced Pipe Inspection failed to identify and evaluate confined space and other hazards in the work area, did not develop and implement procedures for eliminating or controlling flammable gases, and did not adequately inform or train employees about these hazards.

The company has 15 business days from receipt of its citations and proposed penalties to either elect to comply with them, to request and participate in an informal conference with the OSHA area director, or to contest them before the independent Occupational Safety and Health Review Commission.