HOUSTON -- A woman was rescued after a gravel truck lost its load on top of her car on a west Houston freeway Thursday.

"This was a very scary moment and a tragic accident with a tremendous amount of weight," Assistant Fire Chief Rick Flanagan said. "Some 80,000 pounds of contents pancaked her vehicle."

Witnesses helped Houston Fire Department rescue crews dig the woman out.

"The citizens were taking hubcaps and digging her out, removing the gravel," Flanagan said. "Just to look at the magnitude of this accident, you wonder how this person made it out alive.

The woman was transported to a local hospital. Officials said she was conscious and alert.

She was trapped inside her car for about 40 minutes.

One lane of traffic on Interstate 10 eastbound was open to traffic after the rescue.

Officials said the gravel truck overturned near T.C. Jester Boulevard at about 10 a.m.

Investigators are working to determine the cause of the accident.