Inspection Detail

Inspection: 312555295 - Quality Surface Processing

Inspection Information - Office: Appleton Area Office

Investigation Summary

At 9.25 a.m. on February 9, 2010, Employee #1, a 31-year-old employee of Quality Surface Processing, was being trained to strip paint off used towing bar that had been on military vehicles. The towing bar had been patched at another company and delivered to Quality Surface Processing that specialized in chemically-stripping paint, treating, and powder painting. Employee #1 was being trained on dipping this part into a paint-stripping dip tank. The company had done 28 of the same part over the past two years. The dip tank was heated to 850 degrees F and contained a metal-cleaning chemical called Kolene Number 5 or "molten salt bath". This chemical would be considered to be an oxidizing and corrosive material containing alkali nitrates and alkali hydroxides. The liquid was nonflammable, but would react with water, organic materials, concentrated acids, reducing agents, magnesium, tin, zinc, and their alloys. When painted parts were slowly submerged into this heated liquid, a surface flame developed and burned the paint off the metal parts. Employee #1 had completely submerged the part in the liquid and was going to take it out after two to three minutes of soaking. As Employee #1 was waiting the two to three minutes, an explosion occurred in the tank, causing approximately over 80 (missing word) of the liquid to be released. When the liquid was released in its enclosure, the dip tank enclosure latched side and front doors burst open and the double pane safety glass windows of the side door nearest the tank were blown out. During the explosion, Employee #1 was covered with the chemical and was set on fire and was killed. Other organic materials in the area sprayed by the liquid were also set on fire. Employees #2 and #3 helped extinguish the fire and sustained smoke inhalation injuries and minor burns. Employees #2 and #3 were treated for their injuries and then were released. When the part was taken out of the dip tank, it was determined to be the cause of the explosion. One of the welded tube sections (enclosed hollow) was split open most of its length. It was noted that the part had two small holes in it that were recently welded closed by the company that delivered the part. It is highly probable that water was in the hollow frame piece that was sealed and that it would have turned to steam and the pressure would have caused the tubular part of the frame to burst, releasing the steam into the chemical, causing the explosion (violent reaction). The chemical data sheet stated, "avoid all introduction to water it will vaporize to steam and may cause violent eruptions of salt and avoid uncontrolled or excessive introduction of organic materials".

Keywords: BURN, FIRE, EXPLOSION, CHEMICAL REACTION, CORROSIVE, CHEMICAL BURN, DIP TANK, SMOKE INHALATION, CHEMICAL, WATER