Over 50 people were transported to hospitals in Birmingham, Alabama, after a chemical spill occurred at a water treatment plant, fire officials said.
The incident occurred Wednesday at the Birmingham Water Works' Shades Mountain Filter Plant.
"An accidental mix of sodium hypochlorite (which is essentially bleach) and ferric sulfate caused a chlorine off gas at our Shades Mountain Filter Plant. We use these components to treat water as our normal practice, however they are not meant to be mixed together," Birmingham Water Works said in a statement on Twitter.
The company said that initially 14 contractors and one Water Works employee had been taken to the hospital immediately after the spill but that the number had grown by an additional 40 "who were in close contact" with the chemical reaction.
"None have sustained any life-threatening injuries," Birmingham Water Works said in a news release.
Birmingham Fire and Rescue said the 40 people had been taken to the hospital strictly as a precaution.
The chemicals gave off gas as well as a strong odor at the plant, Birmingham Water Works spokesman Rick Jackson said during a news conference.
"Some of the effects people can experience from being exposed to chlorine gas are sneezing, nose irritation, burning sensation and throat irritation, nausea, vomiting or a headache. People may also experience skin irritation or chemical burns and eye irritation," the Mountain Brook Police Department said in a statement.
"It's almost like putting your nose to bleach and sniffing," Jackson said.
Jackson said that there had been no threat to the water itself and that residents could continue drinking and using the water.
"The water supply has not been contaminated. The chemicals have been contained to the building at the facility where the accident occurred," the company said.
Residents were asked to shelter in place for an hour as Highway 280 near the plant was closed. The highway was later reopened.
"As part of its emergency response plan, the Birmingham Water Works is working in conjunction with fire and police departments in Birmingham, Homewood, and Mountain Brook as well as area hospitals, to ensure the safety of employees and residents in the vicinity of the plant. The BWW will conduct a full investigation to determine why the accident occurred, but it has not been determined why the chemicals were mixed at this time," Birmingham Water Works said in its release.