This testimony was offered in response to a court ordered remand directing OSHA to consider applying the one eighth of an inch (1/8in) action level for housekeeping to the entire grain handling facility. Currently the standard has required grain elevators to initiate appropriate cleaning measures whenever grain dust accumulations reach a depth of 1/8in in priority housekeeping areas. NIOSH considered that while the 1/8in limit throughout the industry would improve cleanliness levels, it was considered excessive since dust accumulations of as little as one sixty fourth inch could support secondary explosions if uniformly dispersed into the air. NIOSH has supported research projects at the University of Michigan concerning dust explosions. From the year 1984 to 1987, a total of 69 explosions in agricultural facilities resulted in 15 deaths and 57 injuries to workers. The five components necessary to support a dust explosion were present in all instances: fuel, oxidizer, ignition, mixing and confinement. The quality of housekeeping was poor and a variety of ignition sources was identified including welding, choked bucket elevators, electrical equipment and appliances, and bearings.