Flammable Liquids: What Can You Do With Them?

Too much material with too many vapors and too little ventilation will no doubt create too much of a "boom" that you do not want.

COMPLIANCE requirements for using and storing flammable liquids in the workplace are quite detailed and specific. Unfortunately, the requirements are spread over a number of agencies and multiple documents.

The Occupational Safety & Health Administration provides the regulatory requirement for the workplace in 29 CFR 1910.106. But the agency also adopts and references other standards from other organizations (NFPA, NIOSH), in addition to its multiple standards within 29 CFR related to storage and use. Then, there are "secondary" standards requiring emergency plans, evacuation maps, fire protection, and others because of having flammable liquids in quantity on the premises. And don't forget the whole 29 CFR 1910.120 (HAZWOPER) requirements. For some facilities, there are also the local fire marshal and/or fire protection plans to address, as well.

It is no wonder that, despite all of the articles already written on flammable liquids, people are still confused or, at best, in a quagmire about what to do with the compliance requirements for this category of material. Attempting to obtain all of the compliance requirements can be difficult. Once you purchase the volumes of OSHA standards, you then have to purchase the NFPA standards. Then you have to find time (and interpretation skills) to read all of the volumes of material, including your ability to locate all of the applicable standards scattered throughout those volumes. An online search can create challenges if you don't use the right terminology in your search, so after hours of either reading or searching, you just give up.

No doubt there needs to be a simplified way to address this topic. Of course, we don't want the government's version of "simplification." (Look at what happens to tax laws when they are reviewed and overhauled.) Until something all-inclusive comes along, we are left to our own defenses and thoughts, hoping we are at least favorably looked upon for good-faith efforts in the event of an unforeseen incident that attracts regulatory inspectors and media reporters.

This article is intended to provide you with some practical, real-world practices while reviewing some of the more "elusive" regulatory requirements to help you establish or review potential hazards from your employees' perspective. A regulatory standard does not carry much meaning for an employee who can't see the logic or the sense behind following it, but making the message personal and understanding the hazards based on practices and procedures will help the employee make smart choices that will also comply with the standards--99 percent of the time.

Material Classifications
So let's start with the employee. When using a flammable liquid, what does an employee need to know to protect his own personal safety and health? I'll start with a flammable liquid's hazardous properties.

A material is identified as "flammable" based on the material's ability to create vapor and flash or ignite at certain temperatures, known as its flashpoint. The flashpoint is defined as the minimum temperature at which a material produces enough vapor that, when introduced to an ignition source, will flash/burn. It will not necessarily sustain a flame, but it will ignite and flash. It is the temperature that critically separates a material from being extremely flammable, flammable, or combustible.

This table shows the temperatures and examples that determine these categories:

Extremely flammable liquid

< 73º F

Gasoline (-45º F)

Flammable liquid

< 100º F

Turpentine (95º F)

Combustible liquid

100º = 200º F

Diesel Fuel (104-110º F)

An employee using a flammable or extremely flammable liquid in the work process must recognize and consider the product's flashpoint if using it in a high heat or in an area in which there are ignition sources (welding, cutting, kilns, furnaces, etc).

Because of the low flashpoints, these materials also produce airborne vapors due to relatively low boiling points. Vapors create a couple of hazards. It is the vapor--not the liquid--that burns, so an increase in vapor increases the risk of fire; and many of the vapors create health risks, such as inhaled respiratory disorders, various cancers, and eye irritation, depending on the material in use. In addition to the fire hazard from the flashpoint, an employee can be exposed to double hazards during the use of these products that may require respirators, direct ventilation, or other protection levels such as the correct selection of hand protection.

When using a flammable liquid, employees should keep the cover or lid on the material when it is not in use. This helps to keep the vapors in check, the evaporation of product down, and the health hazards minimized. Where the product will be used also is a factor. Depending on the vapors and the location where flammable vapor-air mixtures may exist, special electrical wiring requirements under Subpart S of the OSHA standards must be addressed to prevent an explosion or flame resulting from arcing or heat.

Transferring a Class 1 (such as gasoline) flammable liquid from one container to another requires grounding the primary container and bonding the primary container with the secondary container with a conductive wire to prevent or dissipate the build-up of static electricity during the flow of the liquid.

Storage Guidelines
Storage of flammable liquids has been a point of discussion and confusion because so much of the discussion centers more on opinion, "best practices," or misinterpretation of the standards rather than the facts. For example, I remember an outside consultant who came to our facility to help with a mock OSHA audit and stated that all of our flammable storage cabinets were required to be vented to the outside. To this day I do not know what his intention was with that demand, but it certainly was not correct. Had we followed his recommendation to vent the cabinets, we would have created a far greater hazard with vapor exposures in high-heat, high-spark environments.

To clarify that point, then, unless there is a local ordinance that requires venting of flammable storage cabinets, there is no requirement. As a matter of fact, the NFPA stated in a formal position letter that "The vents for flammable liquids storage cabinets are not required or even recommended by our Flammable and Combustible Liquids Code, NFPA 30. . . . "

Quantities of stored flammable liquids are regulated according to a number of factors: inside vs. outside a storage cabinet, the classification of the flammable liquid(s) being stored, and the amount(s) of each. For example:

Maximum Quantities Outside a Flammable Storage Cabinet or Inside Storage Room

Class and Container Type


Class IA Liquids in Containers

25 Gallons

Class IB, IC, II or III Liquids in Containers

120 Gallons

Class IB, IC, II or III Liquids in a Single Portable Tank

120 Gallons



Maximum Quantities Inside a Flammable Storage Cabinet or Inside Storage Room

Class of Liquid


Class I or II

60 Gallons

Class III

120 Gallons

Tied with the fire protection standards, there are also limits on the quantity of cabinets you can store together within a facility. In a non-sprinkler-protected area, there cannot be more than three flammable storage cabinets within a fire area. Cabinets that can be separated by at least 100 feet of distance can be stored in groups of three for each 100 feet of separation. In an automatic sprinkler-protected area, six cabinets can be stored within a fire area.

In case you are not familiar with a "fire area," it is defined as an area of a building separated from the remainder of the building by special construction. This area has a fire resistance of at least one hour and has all communicating openings properly protected by an assembly that also has a fire resistance rating of at least one hour.

Also, a flammable storage cabinet must meet certain requirements. You cannot simply "designate" a cabinet for storage of these materials. It must be designed and constructed to meet the NFPA 30 requirements, including the ability to limit the internal temperature to no more than 325° F from the center of the cabinet to within 1 inch of the top of the cabinet when subjected to a 10-minute fire test. Many of the commercially constructed cabinets have self-closing doors in the event of a fire to reduce its spread.

These requirements may be a little deep for what I intended in this article, but these are the areas where I have seen and heard confusion about what is and isn't necessary for setting up a storage area or the type of equipment needed. Although these requirements are based on compliance, certainly you can understand the need for ensuring you don't create a bulk storage facility of flammable liquid unless that is exactly your business. Too much material with too many vapors and too little ventilation will no doubt create too much of a "boom" that you do not want.

This leads to portable containers that have flammable liquids. In a commercial or industrial setting, you are not allowed to store flammable liquids in plastic gas cans. A red plastic gas can with gas or another flammable liquid stored in it that is seen by an inspector will guarantee you a citation. In addition to the regulatory requirement, storing such material in this type of container exposes your employees and your facility or equipment to a real fire hazard.

Have you ever seen your plastic gas can at home become heated and expand or bloat?  Have you ever lost the cap or cover to your plastic gas can at home and found that all the gas evaporated into the air? If you have a gas water heater or other spark producers nearby, this is not a good mix.

In a commercial or industrial setting, such materials must be stored in safety cans that meet certain design requirements: spring-loaded closure, mesh flash guard, and pressure-relief mechanism in the event of elevated heat or fire. These cans are intended for portable, temporary storage of flammable liquids and are not designed to hold more than five gallons. One point of confusion that I have seen is that this requirement is for flammable liquid, not combustible liquid. Going back again to the flashpoints and categories of the materials, this is an important distinction. Kerosene, diesel fuel, mineral spirits, and other combustible liquids do not require the use of safety cans.

To summarize, flammable liquids present real and potentially serious hazards in both safety and health to employees. There are quantity limits based on how flammable a material may be and requirements on how to store those quantities.

Don't forget employee training. Training is a required and important element in keeping employees safe in the use of these materials. From new-hire training to specific task and refresher training, employees need to be reminded of the hazards that are present with these materials and what they can and should do or not do when handling or storing these materials. Training includes fire drills, evacuation drills, reading Material Safety Data Sheets, use of fire extinguishers, selection and use of personal protective equipment when appropriate, and proper task performance.

You are already legally responsible and accountable for ensuring your employees are protected and that your work environment is free of recognized hazards. You as an employer need to encourage your employees to actively participate in locating and identifying workplace hazards so they can be properly and promptly corrected. This includes employee practices through observation and monitoring, as much as it does looking at processes and conditions.

Your job as a manager is to help your people be successful. Set your bar of expectations high so your people have something to attain. They will follow if they know you are sincere in your desire to have and maintain a safe working environment. Remember, your minimum expectation will always be your employees' maximum expectation. So give them a good target and help them hit the bull's-eye.

Your employees are your most valuable asset, and they have much more control in the outcome of their own safety than they may think. Energize them to take that control. As a result of their participation, you create a win-win environment that guides your employees into working safely with flammable liquids.

This article appeared in the December 2006 issue of Occupational Health & Safety.

This article originally appeared in the December 2006 issue of Occupational Health & Safety.

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