1 injured after chemical device explodes in Ore. Porta-Potty

ALOHA, Ore. - Washington County Sheriff's deputies are searching for the person who placed two explosive devices at a public park and inside someone's mailbox on Saturday afternoon.

One woman was hurt by the first explosion inside a porta-potty at Arnold Park around 12:30 pm.

The explosions were caused by mixing chemicals together in a container, like a water or soda bottle, according to deputies.

The device was placed inside the toilet area and exploded several minutes later, when the woman happened to be inside, according to officials.

She was at the park attending a high school girls softball tournament along with 200 players and their families from all over the Northwest.

Shortly after the blast, deputies evacuated the park and searched the porta-potties for additional devices, but did not find any in the park.

"People who heard something thought it sounded like a ball had hit the porta-potty," said RJ Puterbaugh, who was running the snack bar for the tournament.

The victim was visiting from Spokeane and was treated for a bloody head, according to Puterbaugh, before paramedics rushed her to the hospital.

The second explosion happened a few blocks away inside a homeowner's mailbox about 15 minutes later.

Nobody was hurt.

Investigators say both devices were similar to plastic water bottle explosives.

The bomb squad searched the rest of the park and surrounding area gave the all-clear a few hours later.

"We don't know if the device was meant to harm somebody, or just scare folks or create a loud distraction, "said Washington County Sgt. Vance Stimler.

Stimler says authorities would like to catch the person or persons responsible, who may face assault charges.