Post by George Mickiewicz

Chemical Safety Board Outlines Tank Implosion investigation focus We thank the Spokesman-Review for this update The lead investigator at the federal agency looking into the cause of the catastrophic tank collapse has outlined four priorities as they gather information. The area where the U.S. Chemical Safety and Hazard Investigation Board is focusing their investigation to answer why the tank failed are as follows: Mechanisms that led to tank failure. Facility siting. The tank’s maintenance and mechanical integrity. Relevant facility, corporate and industry standards. The brief Thursday presentation did not unpack those investigative priorities beyond stating that “our investigation is ongoing.” The CSB investigation – and the incident reports that are routinely larger than 100 pages – could take years to complete. The nonpartisan federal agency does not impose penalties, but instead is focused on discovering the root cause to help other industrial plants avoid similar tragedies. Kraft papermaking process outlined Wingard discussed how the white liquor tank was used at the pulp paper mill leading up to its collapse May 26. Using a simplified flow chart, he explained that the kraft papermaking process requires very large storage tanks to hold the necessary “liquors” or chemical agents used at different stages. “The liquor goes into a loop,” Wingard said, explaining how liquors are reused. The involved white liquor tank was “immediately upstream” from the “digestor” stage, where the superheated and highly caustic white liquor would be mixed with wood chips to be made into pulp. From there, in simplified terms, the spent liquor gets separated from the pulp and is known as weak black liquor. An evaporator turns it into strong black liquor, a “boiler” stage creates green liquor and a “recausticizer” process converts it back into white liquor. The board’s presentation put the time that the tank failed at 7:08 a.m. May 26. The tank failure created a “wave of caustic liquid that knocked down walls and filled a large portion of the facility. It also reached the Columbia River as well as the ditch system. Eleven people ultimately died and three people were seriously injured in the incident. The injury number is below the tally of eight people injured originally provided by the multi-agency Joint Information Center, which includes the Washington State Department of Ecology and the U.S. Environmental Protection Agency. Board Chairperson Stephen Owens clarified later in the meeting that the federal agency has a more rigid definition for “serious” injuries. For instance, the agency follows a formal guideline for hospital admissions in order to be counted. https://lnkd.in/g2nimN4M