WATCH: Few answers one week after Longview mill plant disaster

“We’re committed to getting to the bottom of this and figuring out what happened,” said L&I Director Joel Sacks.

It was just before 7:15 am on May 26, when a 900,000-gallon tank of white liquor suffered an unexplained catastrophic failure.

The tank partially collapsed, spilling out its corrosive contents, and sending a blast that crumpled nearby vehicles and killed workers gathered in the adjacent break-room. 

Eleven workers were killed, and seven more workers at the facility suffered burns and inhalation injuries, along with one firefighter.

The incident is Washington state's deadliest industrial disaster in nearly 100 years.

L&I noted that in the coming months the agency will be “conducting a detailed investigation seeking answers and accountability.”

The wife of one of the deceased victims has said her husband had talked about safety concerns, but there is no evidence as yet that those concerns were directly related to the vat that suffered a catastrophic failure one week ago.

Mackenzie Ammons told the Seattle Times her husband Jared expressed concerns about conditions there, wondering aloud whether someone would eventually be killed.

L&I is also working to connect families of the workers killed and injured workers to benefits from the state’s workers’ compensation fund, including funeral service cost reimbursement, medical care and wage replacement, and survivor pensions.

Other state agencies remain on site to monitor air and water levels, but to date officials say no contamination has reached the Columbia River since the immediate aftermath of the incident.

Most of the white liquor did not leave the facility site, and cleanup efforts inside the facility continue, officials said.

Washington’s Department of Ecology says all testing shows Longview's drinking water remains safe, but they are still “asking residents to continue avoiding affected sloughs, dikes, and drainage ditches until final confirmation is complete. Please do not attempt to fish in the area. Residents should also keep pets away from these areas.”

On Monday, crews collected 290 deceased fish from ditch systems in locations adjacent to the incident response area bringing the total to 2,226.

Britton Ransford with Washington Fish and Wildlife told The Center Square Monday, they expect those numbers to climb.

“It will increase as flushing operations continue,” said Ransford. “These fish died almost initially due to the high pH levels. Fish like between 6.5 and 8.5 pH and when it gets outside that range it can result in irritation or death. It irritates the gills and makes it difficult for them to breathe.”

Ransford said people who spot dead fish or other impacted wildlife should report that to the WDFW hotline at 1-800-22-BIRDS.

“I think what you're seeing is fish no longer continuing to die, but this was an initial impact, due to direct exposure and as the flushing continues, you're seeing more fish congregate in certain areas that maybe weren't visible. And obviously crews are working to collect fish in those areas at this time.”

Investigators with L&I plan to interview witnesses and conduct intensive physical inspection of the site. Then L&I will make determinations about the root causes of what happened, whether there were violations of safety requirements, and what the penalties are for any violations.