CHICAGO (CBS) — Riders on a CTA bus got a bit of a scare Wednesday morning when a gun accidentally went off after a passenger picked up a small pistol he found on the bus.

WBBM Newsradio’s Bernie Tafoya reports CTA officials initially said an unattended handgun fell off a seat on a #47 bus near the intersection of 47th Street and Kildare Avenue, and went off when it hit the floor.

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However, Chicago police later said a 45-year-old man who was riding the bus picked up the gun from the seat, thinking it was a toy or a lighter shaped like a gun. He quickly discovered his mistake when the gun accidentally went off, and the bullet struck a piece of metal on the bus.

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A woman on the bus felt something strike her thigh — either a fragment of the bullet, or flying debris — but it didn’t even pierce her clothing.

The woman declined an offer from paramedics to take her to the hospital.

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Police said the man who picked up the gun would not face charges, as it was an accident.