As if actual tornadoes weren’t scary enough, a tornado simulation at a museum in Reno, Nev., on Wednesday ended with a chemical flash so strong it left 13 people injured, including eight children, according to the Reno Police Department.

Emergency crews responded to a 911 call from the Terry Lee Wells Discovery Museum late Wednesday afternoon, a Reno police statement said. Several people were treated at the scene, and eight children and one adult were taken to the hospital with minor burns or smoke inhalation, the police statement said.

As of Thursday afternoon, one child remains in the hospital and is in good condition, said Renown Regional Medical Center spokesman Tony Spiker.

Children were sitting a mere six to 10 feet away from the simulation, Reno Fire Chief Michael Hernandez told the Reno Gazette-Journal. The museum runs the experiment as a simulation of a dust devil or tornado, using methyl alcohol and boric acid; but the order of the chemicals got switched and caused a two- to four-second chemical flash, Hernandez said.

Reno City spokesman Matthew Brown told the Associated Press that the demonstration was more of a chemical flash than an explosion, “similar to if someone threw gasoline on a fire.”

The museum issued a statement calling the simulation a “routine experiment,” and that everyone was safely evacuated while no serious damage was done to the building.

“I think at the end of the of the day it’s going to come down to a simple accident in procedure,” Hernandez told the Gazette-Journal. “As the fire chief, I’m not going to call them and say, ‘Please stop doing this procedure.’ The fact is, they’ve been doing this for quite some time. This is probably an isolated event.”

According to a representative, the museum reopened Thursday morning.

This story has been updated.