LONGVIEW, Washington (From news reports) -- New details were revealed in a Nippon Dynawave Packaging report that was sent to the Washington Department of Ecology. The report explains how employees at the paper mill in Longview responded to a massive chemical spill.

On May 26, a tank of white liquor, which is a chemical used to break down wood into pulp, imploded at the paper mill. The breach triggered a major chemical spill, and the incident left 11 employees dead and several others injured.

When the tank imploded, it released 900,000 gallons of white liquor. According to Nippon's report, the incident also damaged a nearby fire main, which added to the volume of spilled material.

Employees at the mill took immediate action, and the report details how they had to decide between diverting the flow of spilled material and intermittently shutting off a series of pumps to control the spill.

Both options resulted in flooding and contamination of the nearby area, including storm drains at the facility, nearby drainage ditches and the Columbia River. At its peak, the report said the flooded area covered 12 acres.

"Our members did what they're trained to do and they did their jobs," Josh Estes, a spokesperson for the Association of Western Pulp and Paper Workers.

The tank failure at the mill is "one of the worst industrial disasters in Washington's history," according to the Washington Department of Ecology. Estes said despite their training, an emergency situation of this scale is not something you can prepare for.

"A tragedy as it is, is not really a circumstance that you can really specifically train for," he said. "But all things considered, our members did what they were supposed to do and took action and I think that's what's important."

According to the report, as of June 23, most of the areas that were impacted by the spill have been cleaned and decontaminated.

"The courtyard area immediately adjacent to the failed tank remains in a controlled exclusion zone," the report states. "Standing liquid material has been pumped/drained from that area, but neutralization and full decontamination of the courtyard area will be completed when it is safe to do so and coordinated with ongoing investigation efforts."

Estes said as more information about the incident comes to light, it will likely change the way employees respond to emergency situations like this.

"There's always an opportunity to learn from an incident... and in any case, take everything that we learn and utilize that and move that forward to improve the operational efficiency and safety of the workers and the facilities that operate in this industry," he said.