Outdoor work and lightning danger often go hand in hand. According to the National Weather Service, 34 percent of the work-related lightning fatalities that occurred between 2006 and 2015 were in farming and ranching. Roofing and construction accounted for 15 percent and 11 percent respectively, while lawn care (9 percent), barge workers (4 percent) and the military (4 percent) also had fatalities caused by lightning. Every year, cloud to ground lightning occurs 20 to 30 million times—striking an average of 300 people in the process. While lightning only kills about 50 people every year, many more of the victims suffer permanent disabilities.
As a construction employer, it’s important that you recognize lightning as a very real workplace hazard. The Occupational Safety and Health Administration (OSHA) suggests all employers with outdoor workers include a lightning safety protocol within their written emergency action plan. This safety protocol should include when specific lightning safety actions should take place, how to notify workers of immediate lightning danger, appropriate safety actions, and necessary response times. Employers should also post lightning safety information at all their outdoor jobsites and review the emergency action plan with affected employees.
Recognizing Lightning Danger
OSHA recommends that construction employers monitor weather reports from the National Oceanic and Atmospheric Administration (NOAA) whenever they have workers on outdoor jobsites. They suggest that employers consider rescheduling jobs when hazardous weather conditions are in the forecast. Employers should also require their supervisors and outdoor workers to watch for the darkening clouds and increasing wind speeds that usually indicate developing thunderstorms.
Responding to Lightning Danger
Put simply, “When thunder roars, go indoors.” According to the NOAA, no outdoor location can offer adequate safety when a thunderstorm is in the area. Whenever possible, your workers should be instructed to retreat to a fully enclosed building if they hear thunder or see lightning. They should remain with in this shelter for at least 30 minutes after the last rumble of thunder.
If a fully enclosed building is not available, your workers should be instructed to retreat to their vehicles and roll up the windows. Again, they should not resume work until at least 30 minutes after the last thunderclap.
If workers do not have access to a fully enclosed building or their vehicles, they should be instructed to avoid utility poles, cell phone towers, cranes, ladders, scaffolding, large equipment, wiring, plumbing, fencing and rooftops. They should also avoid open areas and water. Retreating to a dense area of small trees that are surrounded by large trees or a low-lying area such as a ditch may be their best option.
Lightning Detection Services
Monitoring NOAA weather reports and weather conditions at the jobsite are usually the most efficient ways to identify lightning danger. However, commercial lightning detection and notification services are also an option. These services send an alert when lightning activity moves to within a certain range of the jobsite but they cannot predict the first lightning strike. Portable, hand-held lightning detectors detect the electromagnetic signal from lightning strikes and can estimate distance. But again, they cannot predict where lightning will strike.