In June 2018, a large portion of the ceiling above a Brooklyn Borough Hall subway station platform collapsed, giving a woman a concussion. Now the MTA's Inspector General has issued an audit on the incident, as well as "flaws" in how NYC Transit handles inspecting its stations.

Notably, even though the agency had been monitoring the ceiling, "NYCT engineers relied entirely on ineffective inspection measures and failed to recognize the severity of the structural defect that caused the collapse. Engineers with the proper expertise could have prevented the $8.3 million emergency repair, which is still in place today," the IG's office stated.

IG Carolyn Pokorny wrote in a letter to NYC Transit President Andy Byford, recapping her findings, including that his Maintenance of Way (MOW) Engineering team "lacks the knowledge to reliably assess defects in terra cotta, which is also present in 13 other stations," (Brooklyn Borough Hall's ceiling is made from terra cotta), they "failed to identify and report conditions elsewhere underground that also required timely action and could have created safety concerns," and their "lack of knowledge and resulting delays in seeking repair further resulted in the otherwise unnecessary installation of a 'temporary protective shield' covering the entire Station (platforms and track areas) at what proved to be an exorbitant cost of $8.3 million."

The collapse occurred on the Manhattan-bound 4/5 platform. Molly Scott had been waiting for a train when she "heard something and then all of a sudden stuff was falling on my head." She added, "The only reason that I'm not seriously injured is because I happened to be standing under the reinforced lighting. I believe that the lighting took most of the blow for me, but had I been standing one foot behind where I was, I would have been in much worse shape."

Brooklyn Borough Hall, the IG's office notes, is the 28th busiest station in the subway system and serves over 35,000 daily weekday riders. According to the audit, the ceiling had been visually inspected in March 2017 and January 2018, but while engineers noticed a defect, "they merely confirmed the existence of this defect but took no action to repair it." From the audit:

The supervising engineers who conducted the 2016 enhanced annual inspection admitted to us that they had only limited experience with terra cotta and found it more challenging to rate terra cotta defects than to rate defects in steel or concrete. The maintenance supervisor who oversaw the follow-up annual inspections told us that he and his inspectors treated terra cotta as if it were concrete, though he conceded that the Policy Instruction’s criteria for identifying concrete defects do not clearly apply to those in terra cotta. The maintenance supervisor also stated that he never received guidance or training on how to assess terra cotta. All three individuals told us that the defect at Borough Hall did not seem likely to cause a failure in the near term. However, given their lack of knowledge and experience regarding the construction material involved, the responsibility for properly evaluating the risk should have been transferred to others better qualified to assess it, which likely would have resulted in a timely and less-costly repair and avoided a dangerous collapse.

The IG report cited a 2010 audit of the ceiling collapse at the 181st Street station, which found that MOW Engineers had "insufficient knowledge of arched brick ceilings and suspended ceilings... Subsequently, the agency agreed to our report recommendation for specialty consultants to assist MOW Engineering with assessments of unusual structures and materials. However, we learned during our current audit that MOW Engineering is still reluctant to use such specialty consultants."

A 2012 audit (PDF) also found that NYC Transit had not been consistently inspecting structures on a timely basis.

"It is extremely fortunate that no one was seriously injured in the Borough Hall ceiling collapse last June,” MTA IG Pokorny said in a statement. “Had the recommendations issued in our 2010 report been fully implemented, it is likely that the extensive station damage and costly repairs could have been reduced, if not prevented. The safety of MTA riders, workers, and infrastructure will continue to be a priority for my Office, and I am confident that under current NYCT leadership with President Byford our recommendations will be utilized to prevent future occurrences.”

Following the release of the IG's findings of negligence, an MTA spokesperson simply stated that "when the century-old Borough Hall station ceiling proved defective, engineers assessed the materials involved, shielding the structure, until a full rehabilitation could begin as part of the new capital plan."

Update: The MTA released Byford's response to the audit, where he notes that the issue with this ceiling collapse was not due to a "lack of understanding" about the ceiling, but due to the "absence of specific architectural detail regarding uncommon construction" since the ceiling is over a hundred years old. Also, he says they've already been working to bolster engineers' training.

Additionally, MTA spokesman Tim Minton said, "For years the MTA has been using outside consultants to perform special structural inspections and surveys, in addition to NYC Transit inspections that occur annually. When the century-old Borough Hall station ceiling proved defective, engineers assessed the materials involved, shielding the structure, until a full rehabilitation could begin as part of the new capital plan.”