Paper360 - January/February 2012 - (Page 24)

GAS EXPLOSION MILL WISE PREVENTING Bacterial-Generated Gas EXPLOSIONS A completely preventable accident claims the lives of three employees and serves as a warning for current and future papermakers DAVE VACHAVAKE O n July 29, 2008, my friend Don died in an explosion, along with our coworkers Randy and Steve. The pain of that day was made worse by learning too late that the accident was completely preventable. The two days following the accident were the worst of my life as our mill simultaneously tried to cope with tragedy and understand the cause of the accident. Walking into a control room I saw an article from a trade journal entitled, “Bacteria Cause Fatal Explosion at Corrugating Mill.”1 I wondered how our story got published so quickly and how anyone speculated that bacteria played a role. As I read the article I saw that it wasn’t written about our explosion, but about one that happened at another mill nearly 20 years earlier. Change a few names and details and this article could have been a near-perfect description of our accident. My heart sank. How could such knowledge about the cause and prevention of this type of explosion have existed, and yet be unknown to all of us involved in this tragedy? THE ACCIDENT Millwrights Randy, Steve and Alex went to the top of an 80-foot-high OCC high-density storage tank to weld on a temporary clamp to stabilize a flange connection. After lunch, paper mill superintendent Don climbed to the top of the tank to check on how the job was going. At some point the hot work caused a spark to enter the top of the storage tank, triggering a hydrogen gas explosion that threw Don and Randy to the ground below. Alex had been observing the work from another catwalk and survived with minor injuries. Steve was badly injured but was still at the top of the tank. Risking their own lives, mill rescue workers were able to reach him, but his traumatic injuries were too great to overcome. INVESTIGATIONS Subsequent investigations by OSHA, the Chemical Safety Board (CSB), and independent studies supported the nearly 20-year-old trade journal article. Naturally occurring bacteria had acclimated to normal mill conditions and then thrived under ideal conditions in whitewater and pulp storage tanks. These tanks carry significant amounts of dissolved solids, including starches and simple sugars that are a preferred food source for acidifying hydrogen-producing bacteria in the spore-forming Clostridium family. Starches are applied during the corrugating process and introduced to the paper mill with the OCC used to supplement virgin fiber for 24 Paper360º JANUARY/FEBRUARY 2012

Table of Contents for the Digital Edition of Paper360 - January/February 2012

Over the Wire . . . News Summary
Thinking Small Is Leading to Big Changes
Who’s in Control in the Packaging Industry?
The Problem of Paper Curl
Preventing Bacterial-Generated Gas Explosions
Environmental Challenges for the Coming Decade
Association News

Paper360 - January/February 2012