O'FALLON, Mo. (KMOV.com)--- Hazmat crews are working to clean up a chemical spill that began early Wednesday morning near a business in O'Fallon, Mo.
Emergency crews were called to the 800 block of Hoff just after 8 a.m. for a reported organic peroxide leak. St. Charles County officials said the chemical started to produce a gas, causing a concern.
More than 12 people were treated for possible respiratory issues at the scene but it is unknown where the leak started.
The leak was contained within 30 minutes and there is no current threat to the public at this time, officials say.
All nearby businesses were alerted and one business was evacuated as a precaution.
No additional information has been released.