NAZARETH, Pa. -- A postal worker is back to work after suffering chemical burns when liquid from an exploded soda bottle bomb splashed on her as she opened a mailbox outside an eastern Pennsylvania home.

Police say Patricia Matolyak was splashed by a bubbling liquid last week while delivering mail in Bushkill Township, Northampton County.

Bushkill Township police say a water bottle, foil and a liquid believed to be drain cleaner were in the mailbox when Matolyak opened it Thursday. The makeshift bomb had already exploded but the pooled liquid splashed on the postal worker's arms, hands and face, causing first-degree chemical burns.

Matolyak returned to work on Monday. No arrests have been made.