The willful and serious breaches by Campbell Construction and S&R Contracting led to the collapse of a large masonry wall onto a thrift store, according to the Occupational Safety and Health Administration.
"If these employees had simply followed the most basic safety precautions, no lives would have been lost," said David Michaels, an assistant secretary in the U.S. Labor Department.
The companies' respective owners, Griffin Campbell and Sean Benschop, have 15 days to respond to the citations. Their lawyers did not immediately return calls for comment Thursday.
Workers had been knocking down a vacant four-story structure in June when an unsupported wall crashed down onto an adjacent Salvation Army store filled with shoppers, killing six and injuring more than a dozen.
The demolition site was chaotic and dangerous, according to the 12 citations issued Thursday. Campbell, the prime contractor, was fined $313,000 for violations such as not razing the building from the top down; leaving an unsupported wall more than one-story high; failing to commission an engineering survey; and not providing hard hats for employees.
Benschop's firm, a subcontractor, was penalized $84,000 for violations, including failing to provide employees with fall protection and allowing the unsupported wall to stand.
Benschop himself remains the only person criminally charged in the case so far. He faces six counts of involuntary manslaughter for allegedly operating heavy equipment while high on marijuana and painkillers.
A grand jury has been investigating the case for months. Lawyers representing survivors and the families of those who died also want to hold responsible the owner of the site and the Salvation Army; both have been named as defendants in lawsuits.
Philadelphia-area OSHA director Domenick Salvatore said in a conference call with reporters that "other entities" remain under investigation, but he would not name them. OSHA has another three weeks - until the six-month anniversary of the accident - to issue any remaining citations.
Attorney Robert Mongeluzzi, who represents six survivors and the relatives of two victims, expressed doubt that the penalty money would ever be collected. But he said what's significant is "not just the citations, but the factual underpinnings for the citations."
"This was not an unforeseeable catastrophe," Mongeluzzi said.
Michaels, the assistant labor secretary, noted that OSHA fines are capped by law. He described the amounts involved here as "infrequent" and called the accident "an egregious case."
"While these penalties may be small comfort to the victims and their families," Michaels said, the agency wanted to send a message that "cutting corners on safety will be punished."