A mobile crane at a Kirkland construction site tipped over Monday morning, injuring the operator, who was trapped inside for an hour.

Firefighters and police from Kirkland, Redmond and Bellevue responded to reports of the toppled crane shortly after 8 a.m. at 5501 Lakeview Drive, according to the city of Kirkland. It’s unclear what caused the crane to tip.

The operator was hurt and was taken to Harborview Medical Center  in Seattle, where the operator was in satisfactory condition, according to Harborview spokeswoman Susan Gregg. No other injuries were reported.

A state Labor & Industries representative will investigate the incident, which occurred at the site of a new office building in south Kirkland.