NIOSH REPORTS:
Rare Explosive Hazard With
Sealed and Filled Plow Frame/Toolbar

The National Institute for Occupational Safety and Health (NIOSH) recently investigated ignition incidents resulting from drilling holes into sealed and filled plow frame sections. A farmer and worker were seriously burned in two separate incidents that occurred in the same county in New York under similar conditions. The best explanation of this rare event was from D. Murphy of PSU who did uncover further details outlined from his latest newsletter below.

NIOSH investigated and found the plow frame manufacturer ( Brillion Iron Works in Wisconsin) had filled the hollow frames with scrap metal ballast. The uncleaned assorted machine shop metal scrap apparently reacted electrochemically with water and emulsion-type cutting oils to form hydrogen gas. This concentration of hydrogen gas was found to increase over time under this sealed condition. This gas was nearly pure hydrogen at absolute pressure of 185 psi, more than 12 times atmospheric pressure.

Although the reported ignitions involved plows from the same manufacturer, the use of scrap metal fill may not be unique to plows or to that manufacturer.

Safety Tip: I checked with two major farm machinery manufacturers; they did not fill the frame with anything or used concrete. This scrap ballast method of adding weight to tool bars/plow frames is not common practice. However, the potential for such ignitions exists in any equipment with similar mixed metal scraps and cutting oils/material used as ballast in sealed compartments during drilling, cutting, welding, or other operations that both release the gases and provide an ignition source.