Data from the Mine Safety and Health Administration (MSHA) show that from 1990 to 2004 fatal electrical accidents decreased by 50%, lost workday electrical accidents decreased by 75%, and lost workdays decreased by 60%. Nevertheless, electrical accidents remained the fourth leading cause of on-the-job death in mining. The goal of the NIOSH electrical safety research program is to forge innovative solutions to existing and emerging problems in mine electrical safety. Research has focused on a variety of topics, including trailing cables, motors, trolley systems, ground fault protection, intrinsic safety, explosion-proof enclosures, overhead power lines, and lasers. For example, several aspects of electrical safety research have contributed to new and proposed changes in mining safety law that will dramatically increase high-voltage electrical safety and expedite new technology into the marketplace. Other electrical safety research is leading toward new safety standards for equipment that operates near high-voltage power lines.

Demand for larger, more powerful mining equipment stimulated the need for increased voltages for coal mine face machinery. Several NIOSH studies showed that higher voltages were feasible. The resultant research reports provided technical information to MSHA that was used to help formulate new regulations. These regulations went into effect on May 10, 2002, and allowed the use of high-voltage longwall machines in coal mines. The reports also contributed to the formulation of proposed new regulations for high-voltage continuous miners. These are now in the formal rulemaking process.

MSHA data show that nearly one-fifth of mine electrical deaths occur when workers contact overhead power lines. Research to protect workers from overhead power line electrocution led to one patent and stimulated two U.S. manufacturers to introduce stand-alone power line contact alarms.

Laser technology has become common in several fields, e.g., surveying and level detection. The use of lasers in potentially hazardous underground atmospheres was recognized as a new area of concern. Research was done to measure the risk of igniting flammable atmospheres by radiation from optical equipment. American National Standards Institute and International Electrotechnical Commission standards are now in process, based in part on NIOSH laser ignition research. These standards will result in safety guidelines for the safe use of lasers in gassy and dusty atmospheres.

These and other contributions of the NIOSH electrical safety research program have led to improved electrical safety for the U.S. mining workforce.