The District’s Department of Forensic Sciences in Southwest had to update its safety and quality procedures after a worker left a faucet in a sink running overnight in one of its laboratories, causing hundreds of gallons of water to flood parts of the facility.

The incident happened on Oct. 31, Halloween night, officials confirmed Thursday. Anthony Tran, director of the public health laboratory division, and Jean-Francis Varre, an area manager for the facility, said the water from the faucet drained through pipes under the fourth floor where the lab is located and into three 325-gallon tanks located beneath the facility.

However, so much waste water flowed into the tanks that they overflowed, causing water to flood the fourth floor, then flow down onto the three floors below.

The District failed to report the incident publicly at the time. It cost the city $27,000 in repairs. The DC Line was the first to report the incident earlier this week.

Tran said the sink where the flood started was located in the public health laboratory where workers focus on bioterrorism. The officials said no samples or evidence were affected by the flood, as they are contained in special, secure vaults, nor were any hazardous chemicals or infectious wastes in the water.

Tran said the Centers for Disease Control and Prevention, which investigated the flooding, confirmed no hazardous wastes were released.

The Department of Forensic Sciences building in Southwest Washington in July 2015. A faucet left on in October 2018 cost the city $27,000 in repairs. (Sarah L. Voisin/The Washington Post)

The $220 million, state-of-the-art facility opened in 2012. The building is also where evidence in criminal cases is reviewed for DNA, the city’s chief medical examiner is located, and autopsies are performed.

Officials said they have now implemented new safety measures that include more vigorous safety checks of moisture systems and requiring engineer inspectors to conduct two checks each day, as opposed to only one. The new procedures also include signs near sinks to remind workers to shut off water before leaving a room.