Residents in South Charleston in West Virginia were under an order to shelter in place for around 35 minutes on Thursday morning.
The guidance was first issued at around 6.25am after officials announced that a minor chemical incident had occurred at the Clearon plant in the area, with a slight haze and the smell of chlorine being detected, according to West Virginia Metro News.
The president of the Kanawha County Commission, Kent Carper, said a drum with 30 gallons of bleach tablets was decomposing and led to the haze and odour, the local outlet reported.
The South Charleston Fire Department was in charge of the response and a water curtain was put in place. Shortly after 7am, the shelter in place order was lifted.
South Charleston is around four miles to the west of Charleston, the state capital.