Lightning Safety When Working Outdoors

Lightning strikes can severely injure or kill workers whose jobs involve working 

outdoors. Lightning is often overlooked as an occupational hazard, but employers 

need awareness about lightning hazards to ensure their workers’ safety. This fact 

sheet provides employers and workers at outdoor worksites with lightning safety 

recommendations from the Occupational Safety and Health Administration (OSHA) 

and the National Oceanic and Atmospheric Administration (NOAA).

Introduction

Lightning is a dangerous natural force. Annually 

in the United States, cloud-to-ground lightning 

occurs 20 to 25 million times and over 300 

people are struck by lightning. During the past 

30 years, about 50 people, on average, have 

been killed by lightning strikes every year, and 

many more suffer permanent disabilities.

Precautions should be taken to prevent worker 

exposure to lightning. Employers should 

recognize lightning as an occupational hazard. 

Supervisors and workers at outdoor worksites 

should take lightning safety 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:

• Logging

• Explosives handling or storage

• Heavy equipment operation

• Roofing

• Construction (e.g., scaffolding)

• Building maintenance

• Power utility field repair

• Steel erection/telecommunications

• Farming and field labor

• Plumbing and pipe fitting

• Lawn services/landscaping

• Airport ground personnel operations

• Pool and beach lifeguarding

Figure 1: Lightning strikes tall tree.

Photo: NOAA

Reducing Lightning Hazards When 

Working Outdoors

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. 

FactSheet
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When thunder roars, go indoors!

If you hear thunder, even a distant rumble, 

get to a safe place immediately. 

Thunderstorms always include lightning. 

Any thunder you hear is caused by lightning!

NOAA advises that nowhere outside is 

safe when thunderstorms are in your area.

OSHA and NOAA recommend that employers 

and supervisors follow these lightning safety 

best practices for workers whose jobs involve 

working outdoors: 

Check NOAA 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. 

Figure 2: Lightning strikes a communications tower.

Photo: NOAA

Seek Shelter 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.

Emergency Action Plan

Employers should have a written Emergency 

Action Plan (EAP), as outlined in 29 CFR 1910.38

or 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. 

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. 

Figure 3: Cranes are especially vulnerable to lightning.

Photo: NOAA
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What is lightning?

Lightning is a giant spark of electricity 

in the atmosphere between clouds or 

between a cloud and the ground. 

Lightning can occur:

• Between the cloud and the ground 

(cloud-to-ground lightning)

• Within and between thunderstorm 

clouds (intra- and inter-cloud lightning) 

For more information, see: 

www.nssl.noaa.gov/education/svrwx101/

lightning/faq

Lightning Safety Training

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

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.

Figure 4: Preparedness reduces lightning risks.

(For NOAA toolkits for organizations and large venues see: 

www.lightningsafety.noaa.gov/toolkits.shtml)

Photo: NOAA

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. 

In addition, 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.

For situations which require advance notice of 

thunderstorms, NOAA recommends monitoring 

forecasts and radar observations from either 

commercial weather services or NOAA to stay 

informed of changing weather conditions.

If Caught Outside in a Thunderstorm

If you find yourself caught outside during a 

thunderstorm, there may be nothing you can do 

to prevent being struck by lightning. There simply 

is no safe place outside in a thunderstorm. This 

is why it is very important to get to a safe place 

at the first signs of a thunderstorm. If you are 

caught outside 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). 
4

Water does not attract lightning, but it is an 

excellent conductor of electricity. For boating 

safety see NOAA PA 200252.

• 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).

OSHA Standards

Under the General Duty Clause, Section 5(a)(1) of 

the Occupational Safety and Health Act of 1970 

(OSH Act), 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.” The courts have interpreted 

OSHA’s general duty clause to mean that an 

employer has a legal obligation to provide a 

workplace free of conditions or activities that 

either the employer or industry recognizes as 

hazardous and that cause, or are likely to cause, 

death or serious physical harm to employees 

when there is a feasible method to abate the 

hazard. This includes lightning hazards that can 

cause death or serious bodily harm.

During storms or high winds, OSHA prohibits:

• work on or from scaffolds (29 CFR 1926.451(f)(12));

• crane hoists (29 CFR 1926.1431(k)(8)); and

• work on top of walls (29 CFR 1926.854(c)).

In these situations, scaffold work may continue 

only if a qualified person determines it is safe 

and personal fall protection or wind screens are 

provided. Crane hoists may continue only if a 

qualified person determines it is safe.

Helpful Resources

• NOAA Lightning Safety on the Job, 

www.lightningsafety.noaa.gov/job.shtml

• National Fire Protection Association (NFPA):

• NFPA 780: Standard for the Installation of 

Lightning Protection Systems, 2014 Edition, 

www.nfpa.org/codes-and-standards/documentinformation-pages?mode=code&code=780

• National Lightning Safety Institute, 

lightningsafety.com

• National Aeronautics and Space Administration 

(NASA), Global Hydrology Resource Center, 

Lightning and Atmospheric Electricity 

Research, thunder.msfc.nasa.gov

• Transportation Research Board of the National 

Academies,aProtecting Airport Personnel from

• Lightning Strikes, onlinepubs.trb.org/

onlinepubs/acrp/acrp_iop_004.pdf

Contact NOAA

For information on lightning safety, or to obtain 

data, educational and outreach materials, and 

posters, visit NOAA’s lightning safety website: 

www.lightningsafety.noaa.gov or the WRN

program at noaa.gov/wrn. Contact NOAA at 

wrn.feedback@noaa.gov. Examples of data 

available from NOAA are provided below.

Figure 5: Work-related lightning fatalities Figure 6: Annual lightning fatalities
Contact OSHA

For more information, to report an emergency, 

fatality, inpatient hospitalization, amputation, or 

loss of an eye, or to file a confidential compliant, 

or to request OSHA’s free On-site Consultation 

Program services for small and medium-sized 

businesses, contact your nearest OSHA office, 

visit www.osha.gov, or call OSHA at 1-800-321-

OSHA (6742), TTY 1-877-889-5627.

Workers’ Rights

Workers have the right to:

• Working conditions that do not pose a risk 

of serious harm.

• Receive information and training (in a 

language and vocabulary the worker 

understands) about workplace hazards, 

methods to prevent them, and the OSHA 

standards that apply to their workplace.

• Review records of work-related injuries 

and illnesses.

• File a complaint asking OSHA to inspect 

their workplace if they believe there is a 

serious hazard or that their employer is not 

following OSHA’s rules. OSHA will keep all 

identities confidential.

• Exercise their rights under the law without 

retaliation, including reporting an injury or 

raising health and safety concerns with their 

employer or OSHA. If a worker has been 

retaliated against for using their rights, they 

must file a complaint with OSHA as soon as 

possible, but no later than 30 days.

For more information, see OSHA’s Workers page.

OSHA - DTSEM FS-3863 05/2016

U.S. Department of Labor