An evaluation of the impact of OSHA's control of hazardous energy (lockout/tagout) standard on fatal occupational injury

Purpose. This study evaluates the impact of OSHA's Control of Hazardous Energy (Lockout/Tagout) Standard on fatal occupational injury rates and on the circumstances surrounding lockout/tagout-related fatalities.; Background. "Lockout/tagout" is the practice of shutting down and disconnecting power from machinery or equipment and placing locks and tags on energy-isolating devices to prevent activation of the equipment during maintenance or servicing. OSHA's Lockout/Tagout Standard, which took effect in 1990, requires employers to establish an energy control program and sets minimum criteria for energy control procedures, training, inspections, and hardware.; Methods. An interrupted time series design was used to determine the standard's effect on fatal occupational injury rates per 100,000 production worker full-time equivalents. Machinery-related fatalities, obtained from the National Traumatic Occupational Fatalities (NTOF) surveillance system, were used as a proxy for lockout/tagout-related fatalities. Regression modeling was used to control for demographic and economic factors. A narrative text analysis of OSHA accident investigation reports from 1984 to 1997 was performed to compare the circumstances surrounding lockout/tagout-related injuries before and after the standard.; Results. The average annual crude rate of machinery-related fatalities in manufacturing changed little pre-standard, but declined 4.59% per year post-standard. When demographic and economic factors are controlled for, this pre--post difference disappears. When fatality rates in comparison groups that should not have been affected by the standard are also incorporated into the analysis, there is still no significant relative decrease in the rate of machinery-related fatalities in manufacturing.; Circumstances surrounding lockout/tagout-related fatalities are remarkably consistent pre- and post-standard. Lockout/tagout-related incidents tended to involve the same types of activities and the same level of use of energy control procedures pre- and post-standard. The proportion of incidents in which lockout was definitely not attempted also remained remarkably constant (decreasing just a non-significant 2.4%, from 59.6% pre-standard to 57.2% post-standard).; Conclusions. There is no evidence that the standard decreased fatality rates relative to other trends in occupational safety over the study period or significantly changed the circumstances surrounding lockout/tagout-related fatalities. A low level of compliance with the standard could explain the failure to find any significant impact of the standard.