Anaheim police said the small blast happened around 5:30 p.m. in a trash can.
"A water bottle and some dry ice inside, they close up the bottle. At some point, the bottle fails and that what causes that noise," said Sgt. Bob Dunn of the Anaheim Police Department.
There were no reports of injuries or property damage, but some visitors said they startled by the noise.
"It sounded like a gunshot, but more full. It was sort of a boom and it was loud enough that it sounded very out of place," said Allen Wolf, a witness. "In an area full of young children and that's very cheery, it's not something you expect to hear."Disneyland officials said the evacuation was conducted out of an abundance of caution.
The Orange County Sheriff's Department bomb squad was sent to the park as standard operating procedure and cleared the scene. Toontown was re-opened to visitors.
Investigators said it's not clear who left the dry ice, why they would or where they material came from.
"I don't know what the extent of the charges would, be but it could include fine, the bill for the response, up to including jail time," Dunn said.
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