Photo: The Canadian Press

British Columbia's workplace safety agency has released the first official account of a "Deadpool 2" stuntwoman's death, saying SJ Harris was thrown off a motorcycle and propelled through a plate glass window.

The initial incident report issued by WorkSafeBC confirms witness accounts and adds new details to Monday's tragic crash in Vancouver during filming of the sequel to the popular superhero movie.

The report, which only refers to Harris as the "worker," says she had been rehearsing a stunt that involved driving a motorcycle out the open doors of a building, across a concrete pad and down a ramp that had been built over three stairs before coming to a stop.

"During the first shooting of the scene the stunt driver continued driving beyond the planned stopping spot on the stairway landing, and continued to drive down a second ramp built over the bottom stairs and across the roadway," it says.

"The motorcycle struck the concrete sidewalk curb, the worker was thrown off the motorcycle and propelled through a plate glass window of a building."

The coroner's service has said Harris, 40, of New York City, died at the scene. Friends have identified her as a pioneering motorcycle racer who was an inspiration to African-American women pursuing the sport.

WorkSafeBC is continuing to investigate and has asked the local production company to conduct both a preliminary investigation, which was due Wednesday, and a full investigation, due one month from the incident.

The full investigation is required to determine the cause of the crash, identify any unsafe conditions, acts or procedures that contributed to it and outline what will be done to prevent similar incidents in the future.

Film studio 20th Century Fox confirmed that a preliminary report was submitted on Wednesday, but did not immediately comment further on the WorkSafeBC report.

Witnesses said Harris appeared to lose control of the motorcycle before swerving to avoid a pedestrian and crashing into the glass window of the Shaw Tower in downtown Vancouver.

Filming for the Marvel Comics superhero film resumed 48 hours after Harris died.