Lightning Safety

In the preparation of an Emergency Action Plan (EAP), weather emergencies must be addressed for both outdoor and indoor activities. Weather emergencies include storms involving lightning, flooding, tornadoes, winter storms, and extreme heat and cold weather.

This article will address the emergency procedures for workers in both outdoor and indoor areas to prepare for and conduct operations during storms involving lightning and thunder.

A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm having lightning and thunder. Thunderstorms are usually accompanied by strong winds, heavy rain and sometimes snow, sleet, hail, or no precipitation at all.

Certain meteorological terms are used to provide alerts and warnings of potential storms. Generally, a Severe Thunderstorm Watch indicates when and where severe thunderstorms are likely to occur. A Severe Thunderstorm Warning is issued when severe weather has been reported by spotters or indicated by radar.  Warnings indicate imminent danger to life and property to those in the path of the storm.

In the event of any storms with lightning or thunder, workers need to know how to plan, what to do, and how to react to implement the provisions of an Emergency Action Plan.

The first thing is to monitor weather conditions when there is a potential for thunderstorms or heavy rain events. Weather forecasts should be specifically monitored by a Supervisor or Manager for Severe Thunderstorm Watches and Warnings. The monitoring is easy to do with technology and having weather alerts pushed to cell phones and other portable devices by the National Weather Service, commercial weather service apps, and radio/TV stations. The monitoring should also be done by the onsite Supervisor if there are large clouds, dark clouds or if distant lightning is seen or faint thunder is heard. Due to the mobile workforce in construction, oil & gas industry, and similar industries, it is imperative that the information source you are monitoring is for your area.

If a Severe Thunderstorm Watch or Severe Thunderstorm Warning is issued workers must know what to do and not wait for initial direction from a Supervisor or Manager. Actions such as just being prepared to cease operations and take cover when it (or if) it becomes necessary to do so. Workers must also be alert to thunder and lightning in the area, prepare to or secure outdoor objects that could blow away. Plans must be implemented for outdoor activities that should be suspended or postponed if there is a Severe Thunderstorm Warning.

Preparations must be made for ceasing outdoor operations. Because lightning can strike up to 10 miles from a storm, workers should seek safe shelter as soon as they hear thunder or see lightning. Outdoor operations should be stopped (ceased or suspended) when it is determined the approaching thunderstorm is 10 miles or less away from the job site. To determine the distance that an approaching storm is away from the job site, use a lightning meter or similar storm detection device or the Flash to Bang Method. Essentially, for every five seconds between a flash of lightning and the sound of thunder, the storm is 1 mile away. Using the table below, the Flash Bang Method can be easily referred to:

        Flash to Bang Method

It is not a bad idea to post the Flash Bang Method tables on a bulletin board where they can be referenced quickly. It should be noted that “heat lightning” is lightning from a thunderstorm too far away for thunder to be heard.  However, the storm may be heading toward the job site so pay attention to the conditions and weather forecast and weather alerts. Lightning may precede rain, rain should not be the sign that operations should cease.

As soon as outdoor operations are stopped, ceased, or suspended, personnel should take cover in a safe location which include fully enclosed buildings with electrical wiring and plumbing. If safe building structures are not accessible, workers are to seek shelter in hard-topped metal motor vehicles with rolled up windows. Personnel should stay in this safe for the duration of the storm and for 30 minutes after the last observed lightning flash or sound of thunder.

If outside without access to any safe locations described above, do what is necessary to decrease the risk of being struck by lightning by doing the following:

• 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 low-lying 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).
• Avoid wiring, plumbing, and fencing. Lightning can travel long distances through metal
• 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

When working indoors during a thunderstorm, the following recommendations should be followed:

• Stay away from doors and windows.
• Do not use corded phones or headsets for phones.
  • Cell phones and cordless phones may be used safely in a thunderstorm.
• Turn off and unplug appliances, computers, power tools, TVs.
• Avoid using plumbing. Plumbing fixtures can conduct electricity.
• Lightning may strike exterior electric lines inducing shocks to inside equipment. Use a battery-operated radio for updates on the storm.

After the thunderstorm subsides and leaves the area, operations and other outdoor activities should not resume until 30 minutes after the last observed lightning or thunder.

A search for any missing individuals should not be done until 30 minutes after the last observed lightning or thunder. First aid/CPR should be provided per other sections in the Emergency Action Plan. As a point of reference, injured persons do not carry an electrical charge after being struck by lightning. Emergency medical services should be summoned, if necessary.

As with any serious emergency situation, management should be notified as quickly as possible whenever there has been an injury or substantial damage. It should be logged or documented that operations stopped and the length of the stop as well as the reason for the stoppage. This can be done on a daily work log or JSA or similar document. Emergency contact information and notification requirements are usually in a section at the beginning of the Emergency Action Plan.

Training should be conducted as workers are hired, as the EAP is developed initially, if the plan changes, if responsibilities in the plan change, if the plan does not seem to work effectively, or if it seems that workers do not understand the plan. Drills can be conducted simply by asking the workers, specifically, “what would you do if there was a potential for a severe thunderstorm?” Their answers can serve as an assessment as to do they know what to do and if not show, what training the workers need or that the Emergency Action Plan needs to be updated and the workers retrained.

Planning for thunderstorms and following the pre-planned Emergency Action Plan or Emergency Response Plan will make the working conditions safer because workers will know what to do and not have to wait for supervision to tell them initial directions or, worse, wonder what they are supposed to do while doing nothing to protect themselves.

The following references were used:

• OSHA Fact Sheet titled “Lightning Safety When Working Outdoors” Publication 3863
• Article “The Science of Thunder” National Lightning Safety Institute, http://www.lightningsafety.com/nlsi_info/thunder2.html

For more information on developing Emergency Action Plans or Emergency Response Plans, contact Wayne Vanderhoof CSP at RJR Safety Inc at wayne@rjrsafety.com .