It's rare but it happens and many construction workers have died and others have been injured after being struck by lightning on a jobsite. In some cases the employees were working with rebar and it wasn't even raining yet when the incidents occur.
These tragic incidents are proof that lightning is often overlooked as an occupational hazard. However, lightning strikes kill around 50 people a year, many of them are workers who might not realize they are at-risk. Employers need awareness about lightning hazards to ensure their workers’ safety. Employees should learn where you should go to seek shelter plus the locations, objects and materials you should avoid during thunder and lightning storms.
Employers, supervisors and workers should understand lightning risks, characteristics and precautions to minimize workplace hazards. Lightning is unpredictable and can strike outside the heaviest rainfall areas or even up to 10 miles from any rainfall. Many lightning victims are caught outside during a storm because they did not act promptly to get to a safe place, or they go back outside too soon after a storm has passed. If signs of approaching thunderstorms occur, workers should not begin any task they cannot quickly stop. Proper planning and safe practices can easily increase lightning safety when working outdoors.
The Occupational Safety and Health Administration (OSHA) and the National Oceanic and Atmospheric Administration (NOAA) provide employers and workers at outdoor worksites with these lightning safety recommendations.
Check Weather Reports
Prior to beginning any outdoor work, employers and supervisors should check NOAA weather reports (weather.gov) and radio forecasts for all weather hazards. OSHA recommends that employers consider rescheduling jobs to avoid workers being caught outside in hazardous weather conditions.
When working outdoors, supervisors and workers should continuously monitor weather conditions. Watch for darkening clouds and increasing wind speeds, which can indicate developing thunderstorms. Pay close attention to local television, radio and Internet weather reports, forecasts and emergency notifications regarding thunderstorm activity and severe weather.
Getting out of the elements is the safest way to avoid lightning danger. Seek shelter as soon as you see lightning.
In Buildings: Employers and supervisors should know and tell workers which buildings to go to after hearing thunder or seeing lightning. NOAA recommends seeking out fully enclosed buildings with electrical wiring and plumbing. Remain in the shelter for at least 30 minutes after hearing the last sound of thunder.
Vehicles as Shelter: If safe building structures are not accessible, employers should guide workers to hard-topped metal vehicles with rolled up windows. Remain in the vehicle for at least 30 minutes after hearing the last sound of thunder.
Phone Safety: After hearing thunder, do not use corded phones, except in an emergency. Cell phones and cordless phones may be used safely.
If you are caught outside and absolutely cannot get to shelter, follow NOAA’s recommendations to decrease the risk of being struck.
- Lightning is likely to strike the tallest objects in a given area—you should not be the tallest object
- Avoid isolated tall trees, hilltops, utility poles, cell phone towers, cranes, large equipment, ladders, scaffolding or rooftops
- Avoid open areas, such as fields. Never lie flat on the ground
- Retreat to dense areas of smaller trees that are surrounded by larger trees, or retreat to lowlying areas (e.g., valleys, ditches) but watch for flooding
- Avoid water and immediately get out of and away from bodies of water (e.g., pools, lakes). While water does not attract lightning, it is an excellent conductor of electricity
- Avoid wiring, plumbing and fencing as lightning can travel long distances through metal, which is an excellent conductor of electricity. Stay away from all metal objects, equipment and surfaces that can conduct electricity
- Do not shelter in sheds, pavilions, tents or covered porches as they do not provide adequate protection from lightning
- Seek fully-enclosed, substantial buildings with wiring and plumbing. In modern buildings, the interior wiring and plumbing will act as an earth ground. A building is a safe shelter as long as you are not in contact with anything that can conduct electricity (e.g., electrical equipment or cords, plumbing fixtures, corded phones). Do not lean against concrete walls or floors (which may have metal bars inside)
Have an Emergency Action Plan
Employers should have a written Emergency Action Plan (EAP), as outlined in 29 CFR 1910.38 or 29 CFR 1926.35 that includes a written lightning safety protocol for outdoor workers.
This lightning safety protocol should:
- Inform supervisors and workers to take action after hearing thunder, seeing lightning or perceiving any other warning signs of approaching thunderstorms
- Indicate how workers are notified about lightning safety warnings
- Identify locations and requirements for safe shelters
- Indicate response times necessary for all workers to reach safe shelters
- Specify approaches for determining when to suspend outdoor work activities and when to resume outdoor work activities
- Account for the time required to evacuate customers and members of the public and the time needed for workers to reach safety
- Employers should also post information about lightning safety at outdoor worksites
- All employees should be trained on how to follow the EAP, including the lightning safety procedures
An employer’s EAP may include lightning warning or detection systems, which can provide advance warning of lightning hazards. However, no systems can detect the “first strike,” detect all lightning, or predict lightning strikes.
NOAA recommends that employers first rely on NOAA weather reports, including NOAA Weather Radio All Hazards: www.nws.noaa.gov/nwr.
Bottom line: preparedness reduces lightning risks. Know what to do and how to stay safe when severe weather is in the forecast.