A union representing more than 9,000 forestry workers is withdrawing from a coroner’s inquest into the deaths of four sawmill employees because it says it lost confidence in the process to determine what went wrong before and after the blasts.

A coroner’s inquest in Prince George, B.C., was set to provide a final analysis into two separate 2012 disasters, one at a mill in that city and one near Burns Lake. The inquest will continue, but the lawyers for the union, which represented three of the four dead workers, will no longer be able to question witnesses.

WorkSafe BC had botched its investigations and the Criminal Justice Branch declined to lay charges in relation to either blast because it ruled the safety authority’s evidence was likely inadmissible in court. The coroner’s service had said a single inquest into both incidents would be the best way to examine the key questions and give the jury the information needed to consider recommendations aimed at stopping similar deaths.

Lawyers at the inquest discovered last week that the owners of Lakeland Mills in Prince George had hired a forensic engineering firm from Seattle to conduct a parallel investigation immediately after the April, 2012, disaster.

On Monday, Stephen Hunt, United Steelworkers director for Western Canada, said the union was pulling out in part because information from that independent investigation appeared to have been withheld, further damaging the ability of the inquest to determine how and why the explosion happened, what role the safety policies and practices played or how other mills may prevent such a disaster from happening again.

“They did an independent investigation of the [WorkSafe] investigation and they predicated their whole case on that investigation and didn’t share it with anyone else,” Mr. Hunt said Monday afternoon.

However, Cam McAlpine, a spokesperson for Lakeland’s parent company, Sinclar Group Forest Products, said his company was willing to provide any information the coroner deemed relevant and its third-party consulting firm from Seattle had handed over a USB drive containing its uncompleted forensic investigation.

“If they think we’re hiding a report or that we refuse to provide any information from the investigation, then that’s inaccurate,” Mr. McAlpine said.

Mr. McAlpine said he didn’t know why lawyers for the coroner service found out about Sinclar’s investigation only during testimony last week when all counsel were made aware of the work at the outset of the inquest. Coroner spokesperson Barb McLintock disputed this statement, saying lawyers at the inquest discovered the investigation only during questioning of mill management.

Still, Mr. McAlpine said that last week an investigator with the Seattle firm had a 90-minute phone call with the coroner and gave an overview of the findings, which contained “nothing materially significant to change the outcome of the inquest.”

His company hired a firm to conduct the parallel investigation immediately after the blast for insurance purposes and stopped it after “it became obvious that the insurance claim would be settled and that WorkSafe didn’t require us to have our own investigation report,” Mr. McAlpine said.

There was “nothing unusual” about such a parallel investigation, Mr. McAlpine said. The company did not hand the preliminary findings of its investigation over to WorkSafe BC because the agency was considering litigation, Mr. McAlpine added.

British Columbians were horrified in 2012 by two blasts three months apart at Lakeland Mills and Babine Forest Products that killed four workers and injured 42 others. WorkSafe BC attributed both fires to a buildup of sawdust from dry, beetle-killed pine. WorkSafe BC changed the way it handles major investigations after its evidence failed to secure charges in relation to either fire.

Last year, the agency imposed about $1-million in fines against Babine Forest Products and about $724,000 against Sinclar. Both fines are under appeal.

The inquest can issue recommendations to prevent similar deaths, but cannot lay charges or place blame on any party for the fires. Mr. Hunt said United Steelworkers has renewed its call for a public inquiry into what caused the blasts and why they weren’t properly prevented.