When is a dilute solution of methanol considered “hazardous” for purposes of disposal?

Used or waste methanol is considered a hazardous waste in the United States. Waste methanol in concentrations equal to or greater than 24% by weight meets the US Environmental Protection Agency’s definition of an ignitable hazardous waste. Product grade methanol, when disposed, is a listed hazardous waste. Waste methanol, or water contaminated with methanol, is considered a hazardous waste and must never be discharged directly into sewers or surface waters. It may only be disposed of at a licensed facility permitted to handle hazardous waste. Contaminated product, soil, or water with methanol must be moved only by registered transporters in approved, properly labeled containers. The recommended disposal method for methanol is incineration for heating value recovery. Concentrated liquid methanol can be used as secondary fuel in systems compatible with water-soluble waste. Waste methanol is also amenable to reclaiming by filtration and distillation. For more information on methanol waste treatment and disposal consult Chapter 8.6 of the Methanol Institute’s Methanol Safe Handling Manual.

What kinds of drums are recommended for methanol storage, only steel or are some plastics acceptable?

There are no standard or universal answers for questions regarding materials selection for methanol storage. The following information is provided as general guidance only. Mild steel is usually selected as the construction material for methanol storage containers. If moisture and trace amounts of inorganic salts are expected to exist within the container from time to time, then one should consider upgrading from carbon steel to 316 L stainless steel, or even a titanium or molybdenum stabilized grade of 316 L stainless steel. Many resins, nylons, and rubbers, such as neoprene, nitrile (Buna-N), and ethylene propylene (EPDM), are suitable for methanol service, though some are more appropriate in flowing applications and others for static service. One important consideration is that plastic storage containers are more susceptible to physical damage than metal ones (e.g., if dropped or hit by a forklift). Pure anhydrous methanol is mildly corrosive to lead and aluminum alloys, and more so to magnesium, and platinum. Methanol-water solutions can be corrosive to some non-ferrous alloys depending on application and environmental circumstances, including copper alloy, galvanized steel, and aluminum alloy components, and some plastics and composites. For more information on methanol storage consult Chapter 3.2 of the Methanol Institute’s Methanol Safe Handling Manual. 

How much methanol can be stored at a residence for the purpose of home biodiesel fuel production?

Requirements vary substantially by local jurisdiction depending on the Fire Marshall and the building code. According to the International Fire Code, the maximum aggregate quantity of Class IB flammable liquids, such as methanol, in use and storage in a building may not exceed 120 gallons, provided requirements for explosion-proof electrical service, ventilation systems, flammable storage cabinets, fire protection, spill containment, segregation of incompatible corrosive and flammable materials, and issuance of a hazardous materials permit are met. In addition, special restrictions apply to residential buildings, including maximum amount in use of 10 gallons, prohibition against flammable storage in basements, limits on stacking heights, and set back distances for outdoor storage. These restrictions make the typical single family dwelling or apartment unsuitable for biodiesel fuel production. For these reasons, the handling and storage of methanol for home biodiesel production is not recommended, unless substantial and costly safety measures are implemented. For more information on precautions regarding biodiesel fuel production consult Chapter 2.3.3 of the Methanol Institute’s Methanol Safe Handling Manual.

What types of extinguishers should be used to put out small methanol fires?

Small methanol fires can be extinguished with portable, dry chemical extinguishers and/or water spray provided the volume of water is at least four times the volume of the methanol pool. However, this is only advisable if there is a way to contain the water, otherwise the methanol fire can spread. Methanol flame is low temperature and non-luminous, therefore, when methanol catches fire, it burns with a clear blue flame that is very difficult to see in bright sun light. Methanol may be on fire and you may not be able to discern the hazard of a fire by looking for a flame. Methanol vapor can be ignited throughout a wide range of concentrations in air. Large methanol pool fires are best extinguished with Alcohol Resistant Aqueous Film Forming Foam (AR-AFFF) with 6% foam-water proportioning equipment. For more information on methanol fire safety consult Chapter 6 of the Methanol Institute’s Methanol Safe Handling Manual.

How do you clean up small methanol spills?

Small spills should be controlled with sand, earth, or other non-combustible absorbent material, and the area then flushed with water. Larger spills should be diluted with water and contained with sand or other barrier material for later collection and disposal. Spills onto paved or bare ground should be contained by surrounding the liquid with mechanical or chemical barriers, such as sand, vermiculite, zeolite, or absorbent dikes. For small spills, the spill surface should be covered with the absorbent materials or activated carbon to capture the pooled methanol. After use, the contaminated sorbent materials or soil containing methanol should be removed and packed for recovery, recycling, or disposal as hazardous waste. Methanol spills should be kept from flowing into confined spaces, such as sumps, manholes, and utility tunnels, where vapors may be released and accumulate, potentially reaching flammable concentrations. These spaces should be checked for explosive atmospheres prior to re-occupancy. Only properly trained and equipped employees should be allowed to participate in methanol spill control and cleanup operations. For more information on methanol emergency response consult Chapter 7 of the Methanol Institute’s Methanol Safe Handling Manual.

How long is the storage stability of methanol?

Methanol is a stable material when stored in an appropriate container and suitable environmental conditions. It is mildly corrosive to lead alloys. As it is 100% miscible in water, the presence of moisture or trace amounts of inorganic salts can result corrosion of the metal container. Hazardous polymerization will not occur under normal storage conditions. Properly protected from contamination, methanol shelf life is indefinite.  For more information on methanol chemical and physical properties consult Appendix B of the Methanol Institute’s Methanol Safe Handling Manual.

When responding to a highway/rail accidents involving methanol spills, what is the recommended evacuation distance?

Response actions relating to rail tankers apply equally for tankers attached to tractor haul trucks and to tank trailers towed by tractor haul trucks. In the event of a rail car derailment or tanker truck roll over, first responders should treat methanol as highly flammable and highly toxic. The 2008 edition of the Emergency Response Guidebook (ERG2008) recommends an immediate isolation distance of 150 feet (50 meters) in all directions. In the event of accidental release as a result of the accident or some other circumstance that compromises containment, ERG2008 recommends that responders isolate and consider evacuating in all directions from the release to a radial distance of one half mile (800 meters). Ignition sources must be eliminated to a distance of at least one half mile (800 meters). So-called “running fires” may be expected with large volume releases as the ignited material flows out of the tanker. Running fires are particularly hazardous if allowed to flow into sewers and drains. Flashback can be expected. For more information on methanol spill response and fire safety consult Chapters 6 and 7 of the Methanol Institute’s Methanol Safe Handling Manual.

For employees unloading methanol, what PPE is required?  Do they need to wear fire resistant clothing?

Exposure to methanol can occur via inhalation, skin or eye absorption, or ingestion. The level of risk of exposure to methanol will dictate the appropriate level of personal protective equipment required. At a minimum, safety glasses with side shields or chemical safety goggles and task appropriate gloves are recommended. For routine unloading of methanol where splashing or skin absorption is not anticipated, natural fiber clothing (cotton) is adequate. Avoid wearing synthetic fiber clothing when there is a risk of fire from handling methanol. A chemical resistant apron, butyl or nitrile rubber gloves, and rubber boots, and a full face-shield worn over goggles for additional protection, (but not as a substitute for goggles), may be needed where there is a risk of splashing, such as in coupling and uncoupling hoses or lines. Chemical-resistant clothing/materials should be worn if repeated or prolonged skin contact with methanol is expected. Respiratory protection should be selected based on hazards present and the likelihood of potential exposure. Air purifying respirators with organic vapor (OVA) cartridges are not appropriate protection against methanol vapors due to the very short service life of the OVA cartridge before it becomes saturated, and there are no means of knowing when the vapors break through and the cartridge is no longer offering protection. The use of a supplied air respirator with a full face piece operated in a pressure-demand or other positive-pressure mode is the recommended respiratory protection. Personal protection equipment for the responders should, at a minimum, include chemical splash goggles and face shield, butyl or nitrile gloves, rubber boots, chemical resistance coveralls, and provision for supplied fresh breathing air, such as full face, positive pressure SCBA. Fire resistant clothing is only necessary when fighting a fire. For more information on methanol personal protective equipment consult Chapter 4.2.2 of the Methanol Institute’s Methanol Safe Handling Manual.

When are grounding and bonding needed for methanol transfer operations?

Grounding is designed to create a path of least resistance for any generated electrical charge between a conductive object and the earth. Bonding is a measure intended to dissipate static electricity generated during fluid transfer through a conductive or nonconductive material by making a connection between a grounded object and an ungrounded object. Grounding and bonding are especially important in protecting methanol blends from accidental ignition resulting from static discharge when transferring fluids from one container or tank to another. While pure methanol itself is not a static accumulator, it is appropriate to use bonding or grounding for containers, piping, and drums.  An electrical potential difference (PD) can exist between two containers or pipes and bonding neutralizes the PD, reducing the likelihood of a static discharge. Tanks, storage vessels, and drums should be grounded with copper straps or cables equipped with carbide-tipped clamps to ensure a strong electrical contact through nonconductive surface coatings, such as paint. When dispensing methanol from a grounded metal container, it and the associated fill equipment, including dip pipes, conductive hose, and pump, as well as the receiving container should be bonded together. Dip-tube-filling should be used in tanks or vessels to protect against ignition from static electricity generated as a result of liquid falling through air. Extend the pipe to within one inch (25 mm) of the bottom of the receiving container. Start pouring slowly until the container is filled to a level equivalent to two pipe diameters up the side of the fill pipe. Some plastic-lined metal containers should be treated as non-conductive. Plastic containers cannot be grounded and should not be used for Class I Flammable liquids, such as methanol, without expert review. If a plastic container must be used, follow the same procedure as for metal containers. Ensure procedures are in place to ground, and periodically verify grounding. For more information on methanol bonding and grounding consult Chapter 3.2.5 of the Methanol Institute’s Methanol Safe Handling Manual. 

What precautions are needed when welding or torch cutting tanks or containers that were used to store methanol?

Methanol is extremely flammable and releases vapors at or below ambient temperatures. It has the potential to catch fire when hot work such as, welding, brazing, soldering, cutting, heat treating, grinding, and using power-actuated tools, is performed near methanol sources. When mixed with air, methanol can burn in the open. Methanol spills may travel short distances (yards or meters) along the ground before reaching a point of ignition and flashing back. The hazards associated with hot work can be reduced by implementing an effective hot work program that includes prior work authorization, safe welding practices, and a fire watch. For more information on performing hot work safely consult Chapter 4.3.2 of the Methanol Institute’s Methanol Safe Handling Manual.