AUSTIN, Texas — About 12 days after a foamy substance got into the water supply in a South Austin neighborhood, officials have confirmed what contaminated hundreds of residents' water.

The Austin Fire Department confirmed on Feb. 3 that the contaminant was a fire extinguishing agent called surfactant foam. Assistant Fire Chief Arron Woolverton said the soap-like substance was not toxic because it was heavily diluted.

On Jan. 22, hundreds of residents in the Tanglewood Forest Limited District in South Austin were asked not to drink their water after a fire was put out at the Westoak Woods Baptist Church located at 2900 Slaughter Lane.

Joel G. Baker, the Austin fire chief, explained what happened in a letter to all uniformed personnel within the department. 

He wrote that a staffer at the scene of the fire "asked an engine at a hydrant to pump a 3-inch Class A foam line to another engine that had attack lines pulled. This request was made because the attack engine's Class A foam system was out of service. The attack engine was also receiving water from a 5-inch line connected to another hydrant at the time."

This caused the foam to inadvertently flow into the public water supply via the hydrant line, Baker said. Baker said the AFD found out about the incident at 9 a.m. on Jan. 23.

RELATED: Austin Water says water now safe for all uses after contamination in South Austin

That's when Austin Water Utility issued a water notice for the neighborhood. As crews worked to flush water lines and test the water, bottled water was delivered to more than 300 homes, some businesses, an apartment complex, a church, an elementary school and a retail office space.

Officials said two days after the incident that the foam was cleared from the water supply.

Baker said the worst that could come from drinking water contaminated with the foam is a stomachache. He said it is non-toxic and biodegradable.

He added that this incident has never happened in the City of Austin. The fire chief said the chances of this happening in the future is "minute," however he is asking that this scenario be shared with current and future students in the department "so they'll be aware of this potential going forward."

"If one of our engines is sending Class A foam solution to another engine for fire attack or overhaul, the engine receiving the foam solution should not be connected to another water source," such as a hydrant, the fire chief's letter read.

RELATED VIDEO: Lessons learned from Austin's 2018 water outage

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