PORTLAND, Ore. - A sinkhole swallowed a truck in southeast Portland on Tuesday while maintenance crews were responding to a sewer backup problem.

The incident happened around 2:30 p.m. on Southeast Oak Street between 18th and 19th Avenues.  The truck that fell in the hole was a high pressure sewer cleaning machine.

"I was right next to the truck, like five feet away, when a hole opened up and it just went straight down, nose down," said Bruce O'Brien, who saw the whole thing happen.  "The guys barely scrambled out.  I called 911.  One of the guys had like a broken leg or something.  It was the most insane thing I'd ever seen.  Totally off the charts."

Two workers who were in the truck when it went down were taken to the hospital.  The extent of their injuries is unknown.

A natural gas line and water line were ruptured in the accident.  Officials evacuated residents in the area and closed down nearby roads.  Motorists were being advised to use alternate routes.

"I don't really care about my stuff, but my cat's in there," said Audrey Bekeny, who lives at the corner of Southeast 16th and Oak.  She was not home when the truck went into the sinkhole, but arrived later and was told to stay out of her home. 

The gas company is working to repair the break in the line.  Meanwhile, emergency responders are trying to figure out how to get the truck out of the hole.

Officials with the Portland Fire Bureau say a clogged sewer line is to blame.  Recent rain needed a place to go and because of the clog, it churned underground, creating a cavern.