BOULDER CREEK, Calif. -

State officials are still investigating a propane explosion that occurred last month in the Santa Cruz Mountains.

According to fire crews, a propane company was transferring gas from one tank to another on Feb. 19, but a faulty valve led to a leak. The gas ignited when it reached Thomas Brown's exterior heater more than 100 feet away. He and his daughter then saw the fire, which Brown put out with a garden hose before fire crews arrived. A propane worker was injured in the explosion and taken to a Bay Area hospital. His condition wasn't immediately known.

Fire officials spent the next 45 minutes putting out additional fires in the surrounding area on Bar King Road in Boulder Creek.

The California Occupation Safety and Health Administration is investigating. By law, they have six months to determine a cause of the explosion and complete the investigation.