A hazardous materials situation at the Ballston Metro station over the summer likely exposed riders to toxic gas from batteries.
That’s according to a report at this afternoon’s Washington Metrorail Safety Commission meeting.
As detailed in WMSC’s Twitter thread, the incident happened the evening of Thursday, Aug. 11 and involved old backup batteries in the station’s Train Control Room that were boiling over due to improper charging. On top of that, gas was released into the station because of a faulty ventilation system, according to WMSC.
A fire alarm went off after gas was detected coming from the room, prompting an evacuation and a fire department response that was later upgraded to a full hazmat response. But at least one train stopped at the station and let out riders during that time, exposing them to the toxic gas, WMSC said.
The hazmat response was noted on social media by at least two local journalists, but did not otherwise get much attention at the time.
Radio traffic indicates trains bypassing Ballston Metro as @ArlingtonVaFD handles a hazardous materials incident involving batteries. #wmata #metro
— Dave Statter (@STATter911) August 12, 2022
Metro personnel and the fire department responded to the Ballston Station due to a battery fluid spill in an adjacent room. Trains are bypassing the station as a precaution while the spill is cleaned. Shuttle bus service is being provided. #WMATA
— Allison Papson (@AllisonPapson) August 12, 2022
Following the incident, Metro “developed a number of corrective actions to address issues identified during this investigation,” according to WMSC’s thread, which is compiled below.
The first report today, W-0189, relates to an evacuation for life safety reasons at Ballston Station on August 11.
On August 11, 2022, toxic gas from overheated Metrorail batteries filled part of the Ballston Station. These batteries support the uninterruptible power supply – or UPS – for the station’s Train Control Room.
The Arlington County Fire Department determined that a fire alarm was due to gas coming from the battery room at the southeast end of the station.
The Metrorail personnel involved in the response did not know about the battery safety switch outside the room that can be used to cut power.
After forcing entry into the room, Arlington County Fire upgraded the response to a hazmat response. This was 47 minutes after the initial alarm.
At that point, responders communicated that trains should bypass the station and riders should be evacuated for their safety.
During the time the station was evacuated and closed to riders for their safety, one train stopped at and serviced the station, placing riders in hazardous conditions.
n addition, Metrorail did not follow its emergency response processes. This includes the incident command process. Information was also not consistently and clearly shared.
Rail Controllers made general announcements on the Ops 4 channel for some trains to turn off environmental systems when bypassing Ballston Station. No similar announcements regarding the environmental systems or bypassing Ballston Station were made on the Ops 2 channel.
Train Operator who serviced Ballston Station during the evacuation was in the Ops 2 radio territory when the announcements were made on Ops 4 The Ops 2 Rail Controller made an announcement on their channel only after the Train Operator serviced the station during the evacuation.
The investigation shows that Metrorail had kept the UPS in service beyond the end of its useful life, allowing it to run to failure.
The battery charger was not working properly. This led to excess energy being fed into the batteries. In addition – the ventilation unit in the room was not operating correctly, and the separate exhaust fan was also not working.
The batteries overheated. System data indicates the toxic gas release began approximately 15 hours after the improper charging began. The acid in each battery began to boil.
The WMSC had raised similar ancillary room maintenance concerns to Metrorail in the spring, and further documented these issues in our August 4, 2022 Train Control Room order, the week prior to this event.
Metrorail had committed in the spring to special inspections of ancillary rooms for these types of ventilation system deficiencies, but had not continued those inspections until after the WMSC’s order.
Metrorail opened the battery disconnect to separate the batteries from the UPS at about 12:30 a.m. The battery bank later cooled down and stopped emitting the toxic gas.
The power cutoff was delayed due to unclear labelling of cutoffs and insufficient training and communication of actions to take in emergencies related to battery-supplied systems.
Metrorail developed a number of corrective actions to address issues identified during this investigation. In addition Metrorail is implementing CAPs tied to the Emergency Management and Fire and Life Safety Programs Audit, August 4 order, and other related findings.