LOS ANGELES (AFP) - A 22-year-old Disneyland worker has been charged after two explosions which triggered the evacuation of part of the California theme park, officials said on Thursday.

Nobody was seriously injured in the small blasts allegedly involving "dry ice bombs" in the Mickey's Toontown section of the park in Anaheim, southeast of Los Angeles. Initially police said there was only one blast.

Christian Barnes has been charged with possession of a destructive device in a public place, and faces a maximum sentence of six years in state prison if convicted, the Federal Bureau of Investigation (FBI) said in a statement.

Describing Tuesday's alleged incident, the FBI said two water bottles containing dry ice went off separately as he was ending a shift on a vending cart outside Toontown, an area of the park aimed at younger children.

"Sometime after 4.00 pm, a female employee went to relieve the defendant from his shift at a vending cart... Barnes is accused of opening the vending cart, at which time the first water bottle containing dry ice exploded.

Barnes then allegedly took the second device and dropped it in a trash can in Toontown, which would typically be crowded with parents and youngsters visiting colorful homes of Disney characters.

"Several minutes later a custodian was removing trash bags... and removed the bag containing the destructive device. The custodian put the bag on the ground and walked a short distance to clear another trash can.

"While the trash bag was on the ground, the water bottle exploded," it said.

"The investigation is ongoing. Some victims have reported ringing in their ears," the FBI said, adding that Barnes was expected to be held on US$500,000 (S$635,000) bail after being arraigned in Los Angeles on Thursday.

Disneyland spokesman Suzi Brown earlier said: "We take matters like this very seriously and are working closely with local authorities."