RENO, Nev. — A flash fire that injured 13 people, mainly children, at a Nevada science museum happened when an employee applied the chemicals in the wrong order during a tabletop demonstration about the mechanics of tornadoes, officials said Thursday.

Reno firefighters said a three- to five-second blaze erupted Wednesday at the Terry Lee Wells Nevada Discovery Museum after the presenter poured alcohol on a cotton ball that had been dusted with boric acid and partially ignited. The alcohol is supposed to be applied before the boric acid and the flame.

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"It was a simple oversight by the presenter," Reno Fire Chief Michael Hernandez said in a statement. "Our prevention staff will be meeting with museum staff to review demonstration and safety procedures and make appropriate recommendations as necessary."

Several TV news stations got hold of cellphone video footage from the incident, including CBS This Morning.

The Nevada Occupational Safety and Health Administration is investigating the incident, spokeswoman Teri Williams said.

Eight children and one adult were transported to a Reno hospital for minor burns or smoke inhalation, Reno spokesman Matthew Brown said. One child was hospitalized overnight, but all patients had been released by Thursday afternoon, according to officials at Renown Regional Medical Center.

Four other people were treated at the scene, but their ages were not available.

Jackie Rider said she and her family were watching the demonstration, which is supposed to produce a tornado of green fire, when the flames leaped toward her children and niece.

"She was on fire, completely on fire," Rider told KOLO-TV about her niece. "Her hair, her back, her face. My best friend tackled her and was putting her face out with her hands."

Mat Sinclair, executive director for The Discovery, said the facility's primary focus was on its patrons. "All those affected by today's incident continue to be in our thoughts, and we are committed to determining the cause of this incident," he said in a statement Wednesday.

Museum representatives didn't immediately respond to inquiries Thursday about the employee's medical condition or employment status in light of the fire department's conclusions.

The tornado effect is created when a cotton ball soaked with methyl alcohol is dusted with boric acid and then set on fire inside a large glass container. The jar is set on a Lazy Susan, then spun around to create a miniature green whirlwind.

The two chemicals are commonplace and often combined because they can produce green flames, said Vince Catalano, a chemistry professor at the University of Nevada, Reno. Boric acid is a mild solid that is sometimes used in eye washes, while methyl alcohol is a common solvent that produces low-heat flames when burned.

While it is common sense not to put a flammable liquid on a burning substance, Catalano said, "keep in mind that methanol flames are nearly colorless. It might have been difficult to see that the cotton ball was on fire. It's difficult to speculate without knowing all of the facts."

KRNV-TV aired amateur video posted on its Facebook page that offered a glimpse of the flash fire. Run in slow motion, it appears to show a flash and flames falling off an experiment table and onto the floor several feet from a group of children who screamed when it happened.

Hernandez said the museum was evacuated and didn't appear to sustain additional damage.

The 3-year-old museum offers interactive exhibits on weather, wildlife and inventions and draws about 155,000 visitors a year. It reopened Thursday, although the tornado demonstrations have been suspended.

Additional reporting by Mashable