Fires on construction sites aren’t rare – and they can not only cost you a lot of money, they can be deadly. According to the National Fire Protection Agency, fire departments responded to an average of 4,440 fires in structures under construction per year from 2017- 2022. Those fires also caused an average of five deaths, 59 injuries, and $370 million in property damage per year. So what causes them? And what can you do to prevent construction site fires?

Causes of Fires on Construction Sites 2017- 2022

Cooking equipment

Believe it or not, cooking equipment fires are the leading cause of fires on construction sites. Microwave ovens, grills, or hot plates, all pose a fire risk. According to the National Fire Protection Agency (NFPA),  “these fires were usually minor,” but, “they accounted for one-fifth (19 percent) of the reported injuries.”

Electrical distribution and lighting

Electrical distribution and lighting equipment accounted for 15 percent of the fires. And, they also accounted for almost half of direct property damage.


Construction sites can get chilly. Unfortunately, another leading cause of fires on construction sites is from heaters and portable space heaters. This accounted for 14% of construction fires and 39% of injuries according to the NFPA.

Hot work

Hot work like welding, grinding and soldering is also a leading cause of fires. This kind of work can leave a lot of heat behind even long after the work is finished and cause sparks, which can travel pretty far and ignite fires around the worksite. 


Improper disposal of cigarettes and smoking can also cause construction site fires. Smoking on a construction site can be very dangerous because of proximity to flammable substances like chemicals and construction materials. 

Flammable materials

Construction projects often require flammable materials and chemicals. Unfortunately, their presence on the worksite can present a fire hazard. These types of materials can be ignited by a spark or even spontaneously combust if not handled properly.


Construction sites often fall victim to trespassing and vandalism. Unfortunately, sometimes these crimes also involve arson. While fires that were intentionally set only caused 8 percent of the fires, they caused 45 percent of the direct property damage in the NFPA’s study.

Incomplete fire prevention installation

Fire prevention systems like sprinklers, smoke alarms, and fire extinguishers are vital to protect any building. Of course, during construction this equipment may not be finished and installed. This puts unfinished buildings at risk of a fire that can go undetected and cause major damage. 

Ways to Prevent Construction Site Fires

Prohibit the use of grills and hot pans

To prevent the most common type of construction fire, make a clear policy that outlaws the use of grills and hot pans on the construction site. You may also want to prohibit the use of microwave ovens, or create a designated zone to use the microwave away from flammable materials.

Regularly inspect electrical equipment

Make sure that all electrical equipment is installed properly and to the code set forth in NFPA 70®, National Electrical Code®. Keep extension cord use to a minimum and regularly inspect all electrical equipment. 

Allow only authorized heaters and periodically check them

Sometimes, heaters are necessary, especially in very cold climates. However, it is best to prohibit unauthorized heaters and periodically ensure that they are working properly and kept clean. Additionally, make sure to keep heaters away from debris and any flammable materials. 

Keep the site clear of trash and debris

When trash and debris get too close to a heat source they can ignite. Keeping the worksite clear of trash and debris can prevent fires caused by heaters and hot work. Always ensure that there are ample trash cans and disposal areas to promote a clean worksite.

Enforce a no-smoking policy

To reduce or eliminate fires caused by cigarette butts, it is best to enforce an on-site smoking ban. It can also be helpful to create a designated area where smoking is allowed that is far away from flammable materials and that has proper disposal canisters readily available.

Properly store all hazardous and flammable materials

All combustible and flammable materials should be properly labeled, stored, and disposed of. Be aware that some materials can spontaneously combust. For example, when oily rags are stored on top of each other in piles, they can ignite as they are drying. That’s why it is important to always dispose of oil soaked rags in a fire resistant container. Additionally, be sure that you follow all of the manufacturer’s instructions on any chemical or other material you may require for your project. 

Require permits and cool down time for hot work

You can prevent fires caused by hot work by requiring permits for hot work as well as requiring a cool down period of at least 30 minutes. Always ensure that the areas surrounding the hot work are free of debris and any flammable materials. 

Add security measures to prevent arson

Creating security measures such as fencing, motion detectors, security cameras, security personnel, and even drone monitoring can prevent arson related fires.  

Provide fire extinguishers all around the worksite

To prevent small fires from spreading, it is crucial to provide fire extinguishers throughout the worksite. Ensure all employees know where to find them and store them in accessible areas.

Create a fire escape plan

Fires can happen even when you’ve taken every precaution. That’s why it is so important to create a fire escape plan to help keep you and your crew safe. Your fire escape plan should include an easy-to-follow escape route that you can print out, distribute, and post around the worksite. The plan should include:

  • Directions on what to do in case of an emergency.
  • Instructions on what to do during a fire.
  • The building and its layout.
  • Clear routes to be used for evacuation.
  • Post evacuation assembly areas.

For more information on what you can do to prevent fires on your construction site as well as how to make an emergency escape plan see and


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