Thirteen people were hurt, including several children, in a chemical explosion at a museum in Nevada where presenters demonstrating a so-called smoke tornado caused the blast with a faulty mixture, officials said.
Seven children and two adults with non-life threatening injuries were transported to a local hospital, and another four people were treated and released at the Terry Lee Wells Nevada Discovery Museum in Reno where the explosion occurred, said Reno police spokesman Tim Broadway.
The people who were hospitalised had suffered burn injuries, said Matthew Brown, a spokesman for the city of Reno.
Presenters at the museum were trying to create a "smoke tornado" in a visual demonstration they had done before when a faulty mixture of alcohol and boric acid caused the blast, Brown said.
The museum is aimed mainly at children and offers interactive exhibits in geology, astronomy, history and other subjects.
Officials said they did not immediately have details on the ages of the children hurt in the explosion, which they said did not light anything on fire at the museum.