Last month, a fire in a storage trailer containing hazardous chemicals shut down a three-mile stretch of highway in Athens, Maine, as fire crews from four towns put out the blaze. The box trailer housed solvents, propane and other hazardous material. Luckily, firefighters extinguished the flames before they reached most of the combustible materials. The cause? Possibly a discarded cigarette, a combination of chemicals, or the heat generated within the trailer on a warm, sunny day, according to fire officials.

Yes, storing hazardous materials is serious business — with dangerous, potentially catastrophic consequences.

That’s why many facilities draw up detailed hazmat storage policies and procedures that, among other things, ban smoking; specify chemicals to be stored separately; and require labels, warnings, audits, use of approved containers and sufficient ventilation when necessary.

But in too many workplaces, hazmat storage — like housekeeping in general — doesn’t get the attention its risks require. It’s easy to fall into an “out of sight, out of mind” trap when looking to store solvents, gas and oxygen cylinders and any number of chemicals. Complacency creeps in. Employees accustomed to seeing thinners, cleaners, gas cans or pesticides around the shop forget the potentially deadly consequences of poor storage decisions.

Initial assessment

A serious approach to safely storing hazardous materials starts with checking into all applicable local, state, and federal fire codes and safety regs. Make sure you’re in compliance.

Check your material safety data sheets for storage instructions. MSDSs will list safe storage conditions as well as conditions that should be avoided.

If you still have questions, bring in a local fire department or hazmat emergency response squad officials to help with your assessment. Fire and emergency services should be updated regularly on what potentially dangerous materials you have on site, where they are kept, and in what quantities.

Then draft a plan and enforceable policy for storing hazmats. At Clemson University, the EHS department looks to store hazmats in low-traffic, but accessible, areas. The number of storage locations and amounts on hand should be kept to a minimum, according to Clemson’s EHS policy.

Other issues to consider when mapping out storage locations:

Ensure that water flowing from sprinkler heads is not obstructed by storage. Generally, storage of materials must be located 18 inches below sprinkler heads, according to the San Diego Fire-Rescue Department. When there is storage against walls, the storage should not be any closer horizontally to the sprinkler head than four inches.

Never store hazardous materials near open flame or in direct sunlight, according to the Web site EHow.com.

NASA’s hazardous chemicals storage guidelines state that rooms where flammable and combustible toxic materials are stored must have adequate ventilation to prevent chemical vapors from accumulating to flammable levels. The storage area should be free from heat and moisture sources.

NASA also states: “No paper products, office equipment, food, or any other non-hazardous material should be stored in any hazardous material storage cabinet.”

Know your inventory

Inventory control of hazmats is critical. Refer to MSDSs for information about chemical properties. NASA’s policy states that toxic materials must be physically separated from materials not classified as toxic. Plus, toxic materials should be segregated according to the type of material to be stored, according to NASA.

The San Diego Fire-Rescue Department advises that incompatible acids should be stored separately from each other (such as nitric acid, perchloric acid, acetic acid).

Selection of storage cabinets and containers is critical, too. Here’s how specific NASA gets about cabinet requirements for storing acids and bases:

Each cabinet must be rated for use with the hazard class of the most hazardous content stored.

The cabinet must be listed with an approved testing laboratory (UL, FM, etc.) for the intended use.

Cabinets or other storage containers must be designed and rated for use with corrosives by the manufacturer.

Flammable corrosives must be stored in a cabinet rated for both corrosives storage and flammable storage.

Cabinets should have a spill control tray large enough to contain a complete spill from any two containers.

Perforated shelves are not recommended for corrosives storage. Polyethylene shelf trays should be used to protect the shelves from spill damage.

Glass containers of one-gallon capacity or higher should be stored on the lowest shelf. Secondary containment is recommended for glass containers (external bottle shrouds, plastic or stainless steel bottle containers).

Flammable acids and flammable bases must be completely enclosed in unbreakable containers for storage in the same corrosives cabinet or in the same corrosives cabinet as non-flammable corrosives.

Activate awareness

Signs and labels also deserve serious attention. Check for specific regulatory requirements, such as hazard communication labeling. NASA’s policy states: “A room where toxic materials are stored must be clearly identified with highly visible TOXIC MATERIALS signs at all entrances, and doors shall have a National Fire Protection Association Chemical Hazard Rating System sign with hazard explanations.”

States the San Diego Fire-Rescue Department: “All cabinets that contain hazardous materials, whether approved or not, must be labeled on the outside as to its contents. Letters must be at least one inch high.”

NASA also takes these steps regarding labels and markings:

Each cabinet should be numbered and labeled with the contents of the cabinet.

Each cabinet should be clearly labeled as to the hazard class of the materials stored within the cabinet (Acids, Flammables, etc.).

Each cabinet should be labeled with the name, phone number, and organizational code of the responsible person(s).

The human factor

Many of the keys to safe hazmat storage depend on knowing your toxic materials, regulatory requirements, environmental conditions and matching cabinets and containers to your materials. But obviously, you can’t neglect human factors.

Your employees need to be trained and made fully aware of the seriousness of your hazmat storage policies and procedures. Receiving crews should know to segregate hazardous and incompatible materials and use designated storage locations in the facility. No smoking zones must be enforced. Complete and accurate inventories of chemicals and hazardous materials should be maintained. Conduct periodic and annual inspections of storage areas and procedures.

SIDEBAR: OSHA’s checklist — storing flammable & combustible materials

Are combustible scrap, debris, and waste materials (oily rags, etc.) stored in covered metal receptacles and removed from the work site promptly?

Is proper storage practiced to minimize the risk of fire, including spontaneous combustion?

Are approved containers and tanks used for the storage and handling of flammable and combustible liquids?

Are all connections on drums and combustible liquid piping, vapor and liquid tight?

Are all flammable liquids kept in closed containers when not in use (for example, parts cleaning tanks, pans, etc.)?

Are bulk drums of flammable liquids grounded and bonded to containers during dispensing?

Do storage rooms for flammable and combustible liquids have explosion-proof lights?

Do storage rooms for flammable and combustible liquids have mechanical or gravity ventilation?

Is liquefied petroleum gas stored, handled, and used in accordance with safe practices and standards?

Are “NO SMOKING” signs posted on liquefied petroleum gas tanks?

Are liquefied petroleum storage tanks guarded to prevent damage from vehicles?

Are all solvent wastes and flammable liquids kept in fire-resistant, covered containers until they are removed from the work site?

Is vacuuming used whenever possible rather than blowing or sweeping combustible dust?

Are firm separators placed between containers of combustibles or flammables, when stacked one upon another, to assure their support and stability?

Are fuel gas cylinders and oxygen cylinders separated by distance and fire-resistant barriers while in storage?

Are fire extinguishers selected and provided for the types of materials in areas where they are to be used?