So far, the remains of 11 of the 37 victims found have been positively identified and the 13 missing are presumed dead, The (Montreal) Gazette reported.
Genevieve Guilbault of the Quebec coroner's office said along with identifying the victims, autopsies must also be performed and the cause of death determined before a death certificate can be issued, the newspaper said.
"It's a long, difficult process for the families," Guilbault said. "We plan and support the families throughout this time."
The recovery work also posed dangers for the searchers. One officer suffered heat stroke Sunday and another suffered burns to an eye caused by chemical irritants on site, the newspaper said.
Workers also were draining crude oil still in the dozens of overturned tankers strewn about the accident site and decontaminating the soil.
The Montreal, Maine & Atlantic freight train, which had been parked for the night, rolled unmanned into the small town early on July 6, derailing and erupting in flames and explosions.