Hot Work Safety Near Storage Containers

Danger Hot Surface Work

According to the U.S. Chemical Safety Board (CSB), hot work accidents are among the most frequently reported accidents to that agency. Between 1990 and 2010, fires and explosions near flammable storage tanks caused by hot work accounted for more than 60 fatalities.

Unfortunately, these accidents continue to take place. This past July, an explosion occurred during hot work near a storage tank at Omega Protein in Mississippi, killing one worker and injuring another. The tank contained eight inches of water and fish matter, which unknown to workers created flammable gases that led to the accident.

When incidents like this happen, oftentimes the people and companies involved haven’t sufficiently assessed hazards and properly isolated everything in the vicinity that could be flammable.

These types of hot work accidents may not seem as obvious as other hazards associated with hot work such as UV light or welding fumes, but they can be even more deadly. The oil and gas industry often faces these hot work hazards, but so do the food production, paper and wastewater treatment industries, according to a video about the dangers of hot work made by the CSB. 

Storage Tanks, Oil Tanks
An explosion at an oil company in Mississippi occurred when welding sparks ignited flammable vapors from a storage tank. Photo: CSB

What Is Hot Work?

OSHA defines hot work as “any work that involves burning, welding, using fire- or spark-producing tools, or that produces a source of ignition.” Welding and cutting occur frequently at many industrial worksites, so it’s important for workers involved in these operations to understand the potential unseen dangers associated with these tasks. Flammable gases and vapors can be present near storage tanks, fuel tanks and other confined spaces.

Prevent Hot Work Fires and Explosions

In 2010, the CSB published a bulletin offering advice for how employers can prevent these types of hot work accidents. In the wake of recent accidents involving hot work and storage tanks filled with organic matter that might not seem hazardous (as was the case at Omega Protein), the organization has reemphasized the importance of following clear and effective hot work procedures. Their suggestions, along with recommendations from OSHA, should be considered by workplaces that perform hot work.

Assess the Situation

Whenever hot work will be performed, thorough hazard analyses need to take place that determine what possible flammable liquids or gases exist in the area. This includes considering the equipment that will be worked on, but also any other nearby equipment.

In an accident in 2006 at an oilfield (also in Mississippi), workers cleaned and aired out one tank where they would be performing hot work, but another nearby tank containing oil was still highly flammable. This oil emitted vapors as the temperature increased that day, and sparks from welding led to an explosion that killed three workers.

These flammable hazards always need to be isolated, and if that’s not possible, other methods of doing the work (such as cold or hydraulic cutting) should be considered.

Even after assessment and hazard mitigation at the worksite have taken place, it is still important to monitor the conditions throughout the workday. Gas monitoring devices should be used before and during hot work, and work should not proceed whenever a detected flammable or combustible gas exceeds 10 percent of the lower explosive level (LEL), according to OSHA.

In some cases, gas monitoring in the morning might not reveal anything troubling, but as the temperature increases as the day goes on, flammable gases or vapors may emerge from storage tanks. Consequently, monitoring for these substances should be ongoing. 

Prepare Personnel

Assessing and maintaining the safety of the worksite is critical, and for those efforts to be successful, staff needs to understand the hazards of and best practices for hot work.

First, make sure anyone involved in hot work has received proper training about the use of tools that create heat and sparks. These workers must know what the possible hazards are—including flammable gases—and how to perform the work in a safe manner.

This is true for contract workers as well. While contracting companies need to provide training in hot work safety for their workers, if those workers are on your worksite, you need to make sure these people have received training and understand the job. Too many accidents occur because of miscommunications—or a lack of communication—between companies and their contractors. 

Be Prepared for Fires

Hot Work
OSHA recommends having fire extinguishers present during hot work. Photo: OSHA

Whenever heat sources are present, a workplace needs to be prepared for possible fires, however small the odds of a fire occurring may seem. Fire-extinguishing equipment must always be available when hot work is taking place, and OSHA recommends assigning someone to act as a fire watcher during the work. This person is responsible for using fire-extinguishing equipment (if conditions permit), sounding the alarm and making sure a fire doesn’t develop after hot work is complete.

Additional Hot Work Hazards

While flammable gases and liquids near hot work deserve a significant amount of attention, employers and workers should also remember the importance of other basic hot work safety. Other hot work hazards include:

  • Fumes
  • UV Light
  • Sparks
  • Noise
  • Possible Skin Injuries

Workers must wear the appropriate protective gear when performing hot work to stay safe from these hazards. This gear includes face shields, goggles or helmets and welders’ vests and gloves.


OSHA also advises that those doing hot work make sure sufficient ventilation exists in the area so toxic fumes don’t become a problem.

Standards to Reference

For more information about staying safe and compliant while performing hot work, employers should consult the following OSHA standards:

  • 29 CFR 1910.106, Flammable and combustible liquidsHot Work
  • 29 CFR 1910.252, Welding, cutting, and brazing – general requirements
  • 29 CFR 1910.253, Oxygen-fuel gas welding and cutting
  • 29 CFR 1910.254, Arc welding and cutting
  • 29 CFR 1910.255, Resistance welding

The National Fire Protection Association (NFPA) also has standards related to hot work:

  • NFPA 30, Flammable and Combustible Liquids Code (2015)
  • NFPA 51B, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work (2014)

Hot work and flammable gases aren’t the only explosion hazards in the workplace. Learn more about combustible dust in the SlideShare below.

19 Ways to Deal With Combustible Dust from Creative Safety Supply

Additional Resources