What is the primary hazard associated with flammable liquids? Explosion is the primary hazard associated with flammable liquids. They are particularly dangerous because they can produce vapors. When these vapors mix with air and reaches its flashpoint, it can ignite, causing disastrous consequences.

While many substances can pose a fire risk, flammable and combustible liquids, in particular, ignite easily and burn very quickly. 

Investigators discovered a fire and series of explosions occurred in 2007 at a Des Moines, Iowa, chemical distribution facility after inadequate electrical bonding and grounding sparked static electricity as crews filled a portable steel tank with ethyl acetate, a flammable solvent. 

There were no fatalities, but one worker and firefighter were injured. The Des Moines incident also contributed to a $1.1 million civil penalty for the company.

The outcome could have been much worse, which is why companies that utilize flammable or combustible liquids must take enhanced precautions to ensure all safety measures are in place.

To avoid the risk of explosion, here is important information to consider.


How Flammable Liquids Are Classified


If your company works with or stores flammable liquids, it is critical to know how each liquid stored on your property is classified using the National Fire Protection Association (NFPA) classification system.

This classification system is based on a liquid’s flash point, which is “the lowest temperature at which a substance generates a sufficient amount of vapor to form a vapor/air mixture that can be ignited.”

Flammable liquids have a flash point under 100 degrees F. Combustible liquids have a flashpoint at or above 100 degrees F. The lower the flash point, the easier the vapors of the liquid will ignite. 

What is the difference between flammable and combustible liquids? Flammable liquids will catch on fire and easily burn at normal working temperatures. Combustible liquids need heat before they can ignite. 

The NFPA classifies all flammable liquids as Class I. Based on the risk of fire, which can lead to an explosion, these liquids are divided into six sub-classifications.

Flammable Liquids Combustible Liquids
Class IA Class III
          - Flash points below 73 degrees F           - Flash point at or above 100 degrees F, but below                    140 degrees F      
          - Boiling points below 100 degrees F           - Examples include camphor oil, diesel                         fuel, pine tar, motor oil, kerosene
          - Unstable flammable liquids also fall                             under this classification Class IIIA
          - Examples include Ethylene oxide,                                pentane, propylene oxide, vinyl                              chloride           - Flash point at or above 140 degrees F,                     but below 200 degrees F
Class IB           - Examples include formaldehyde,                                 creosote oil, linseed oil, mineral oil
          - Flash points below 73 degrees F Class IIIB
          - Boiling points at or above 100 degrees F           - Flash point at or above 200 degrees F
          - Examples include acetone, ethyl                                  alcohol, isopropyl alcohol, benzene,                      octane, methanol, heptane           - Examples include castor oil, coconut oil,                    fish oil, olive oil, ethylene glycol,                            glycerine
Class IC  
          - Flash points at or above 73 degrees F,                       but below 100 degrees F  
          - Examples include diethylene glycol,                            turpentine, xylene, isobutyl alcohol,                      mineral spirits  

                    Note: According to the NFPA, because Class IA liquids are so volatile, boiling points are used only to distinguish between IA and IB.


How And Where Flammable Liquids Should Be Stored


Explosions can cause catastrophic damage, which is why how and where flammable liquids are stored is critical to ensuring safe operations.

Keep in mind that while there are general procedures all companies should follow, there are also specific requirements for each sub-classification of flammable and combustible liquids as well.

In the state of California, there are specific requirements for the container size and quantities used in a laboratory.

Other storage guidelines include:

  • Keep containers out of the way of traffic, both pedestrian and vehicular. 
  • Never block stairwells or exits with storage containers.
  • Keep flammable and combustible liquids in a fire-proof storage cabinet.
  • Store containers away from ignition sources, including electrical tools, open flames, heat, static electricity and sparks from incinerators.
  • Make sure containers are sealed so they cannot release vapors.

Proper labeling is also an important aspect of storing waste flammable liquids. All containers should at least include:

  • The start date of accumulation for waste
  • The type of liquid
  • A Hazard Class 3 flammable (or other appropriate) logo, which is a picture of a raging fire
  • Additional information on the label mandated by your state and local authorities

Containers must be labeled right away after waste is placed inside.


How To Avoid Explosions


the primary hazard associated with flammable liquidsIn addition to following the storage and labeling guidelines above, it is important to make sure all employees are educated on these procedures in order to minimize the risk for explosion.

This includes ensuring every employee is trained in properly stacking, transporting and storing any flammable or combustible liquids on site. When moving liquids through an area, for example, workers should halt walk to ensure no known ignition sources are present.

Other best practices to keep in mind include:

  • Thorough documentation that can be referred back to if an emergency occurs
  • Storage based on hazard class codes
  • Regular inspection that looks for leaks or deteriorating containers

The creation of a Hazardous Material Business Plan (HMBP) also can provide important information about the hazardous materials on site for first responders. In the state of California, an HMBP must include:

  • Business activities and owner identification
  • An inventory of any hazardous materials on site
  • A site map
  • An emergency response plan and employee training

Hazardous waste disposal codes generally dictate the proper disposal methods for flammable liquids, which assists in preventing catastrophic events.

Before signing on with a company that accepts your flammable liquid waste, make sure it follows best practices for its disposal in a sustainable manner. Temarry Recycling, which recycles solvents at its solvent distillation unit, offers a sustainable and safe method for some flammable liquids. 

The process is part of a Closed Loop Recycling system that ensures nothing is wasted and keeps materials at their highest utility. You can read more about this process, which returns solvents back to industry, in our article, Solvent Distillation And The Energy Recovery Process Explained.


Are you Recycling or Fuel Blending

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