Updated

Twenty students at an elementary school in California became sick Tuesday after they were exposed to tear gas and pepper spray that drifted onto their campus.

The chemicals drifted to Portola Elementary School in San Bruno during a training exercise the San Francisco Sheriff's Office was doing at the nearby San Bruno Jail, according to ABC 7.

The sheriff's office said it was conducting an indoor training session with the chemical agents at the jail when tear gas from the training moved outside and over to the school, which is located a mile away.

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Portola Elementary School

Twenty students at an elementary school in California became sick Tuesday after they were exposed to tear gas and pepper spray that drifted onto their campus. (Google Maps)

Students and teachers felt the burning in their eyes, nose and throat.

The sheriff's office said this has never happened during 20 years of training at the jail.

"We sincerely apologize to Portola Elementary School, its faculty and students, and their families for this unforeseen event which must have been especially scary for children," the sheriff's office said.

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Students and teachers felt the burning in their eyes, nose and throat. (San Francisco Sheriff's Office)

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The sheriff's office said it is pausing all training with chemical agents following the incident.