Nine people working at a plant in Wayne Township, Ind. were injured during an explosion and ensuing acid spill on Friday.
A 250-gallon nitric tank at a Rolls-Royce plant exploded early in the afternoon, reports the Indianapolis Star. It isn't known how full the tank was, nor the cause of the explosion.
Fire crews that responded to the plant said that there was a "chemical cloud" inside the building, but everything was under control.
According to NBC News, eight of the injured employees were taken to either the IU Methodist Hospital or Eskenzi Hospital for acid exposure. The ninth injured person only needed to be treated on site.
All that is currently known about the employees taken to the hospital is that they are said to be in stable condition.
The air around the plant was announced to be safe a few hours after the initial explosion. Indianapolis Fire Department spokesman Patrick Pruitt said, "Now it's just a matter of making sure that we ... get that material neutralized."
Nitric acid exposure can lead to severe burns as well as breathing problems.