Cloud-to-ground lightning occurs 20 to 25 million times every year and workers operating heavy equipment, doing construction, roofing, steel erection, and landscaping are at the top of the list when it comes to who gets hit.
Lightning is an occupational hazard. Take it seriously. Workers whose jobs involve working outdoors in open spaces, on or near tall objects, or near explosives or conductive materials (e.g., metal) have significant exposure to lightning risks. Worker activities at higher risk for lightning hazards include:
- Heavy equipment operation
- Construction (e.g., scaffolding)
- Building maintenance
- Power utility field repair
- Steel erection/telecommunications
- Plumbing and pipe fitting
- Lawn services/landscaping
If you or your employees are employed in one of the occupations above, listen up. Someone cares about you and wants to make sure you get home at the end of the day.
What to know and do
You know most of these tips but there are a few that may surprise you.
It does not have to be raining to be lightning. Lightning is unpredictable and can strike outside the heaviest rainfall areas or even up to 10 miles from any rainfall.
After the rain ends, It does not have to be raining to be lightning. Many lightning victims are injured because they go back outside too soon after a storm has passed.
Seek shelter in buildings and know which buildings are safe. 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 in a thunderstorm - and there is no safe place outside in a thunderstorm - follow these rules:
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. Stay off and away from large equipment such as bulldozers, cranes, backhoes, track loaders and tractors.
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 low-lying areas (e.g., alleys, ditches) but watch for flooding.
Avoid water, and immediately get out of and away from bodies of water (e.g., pools, lakes) Water does not attract lightning, but it is an excellent conductor of electricity.
Avoid wiring, plumbing, and fencing. 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.
As an employer, you have additional responsibilities for lightning safety.
Train workers on lightning safety. Employers should adequately train all workers on lightning safety. Training should be provided for each outdoor worksite, so that supervisors and workers know in advance where a worksite’s safe shelters are and the time it takes to reach them. Employers should train supervisors and workers to provide lightning safety warnings in sufficient time for everyone to reach a worksite’s safe shelters and take other appropriate precautions
Lightning warning systems: Your emergency Action Plan (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: https://www.nws.noaa.gov/nwr/
Commercial lightning detection and notification services are available to monitor for lightning activity. These notification services can send alerts when lightning activity develops or moves to within a certain range of a work site.
These commercial systems can provide mapped locations of lightning strikes from an approaching storm. However, these systems cannot predict the first lightning strike. Consequently, it is important to watch the sky for storms developing overhead or nearby and get to a safe place prior to the first lightning strike.
Portable and hand-held lightning detectors function by detecting the electromagnetic signal from a nearby lightning strike and then processing the signal to estimate the distance to the lightning strike. These devices typically do not detect all strikes, cannot predict the first strike, cannot provide the location of a strike, and are less accurate than the commercial detection and notification systems. In some cases, simply listening for thunder or watching the sky may be a better indication of a developing or nearby storm.
Emergency Action Plan: Employers should have a written Emergency Action Plan (EAP), as outlined in 29 CFR 1910.38or 29 CFR 1926.35.
The EAP should include 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.
During storms or high winds, OSHA prohibits:
- Work on or from scaffolds
- Crane hoists
- Work on top of walls
Workers and Employers: Lightning hazards are part of the OSHA General Duty Clause which says employers are required to provide their employees with a place of employment that “is free from recognizable hazards that are causing or likely to cause death or serious harm to employees.”
Employers have the right to insist workers avoid lightning hazard activities, and workers have the right to get themselves to safe shelter when a storm approaches.
If a co-worker is struck by lightning. Lightning victims do not carry an electrical charge, are safe to touch, and need urgent medical attention. Cardiac arrest is the immediate cause of death for those who die. Some deaths can be prevented if the victim receives the proper first aid immediately. Call 9-1-1 and perform CPR if the person is unresponsive or not breathing. Use an Automatic External Defibrillator if one is available.
OSHA offers a downloadable fact sheet titled ' Lightning Safety When Working Outdoors' with excellent reminders on what workers should - and shouldn't - do during summer storms.
Be smart - When thunder roars, go indoors!