Substitution can be the best way to avoid or reduce a hazard. But it is not always easy or even possible to find a suitable, less hazardous substitute for a particular dangerously reactive material used for a certain job. Speak to the chemical supplier to find out if safer substitutes are available. For materials that polymerize easily, use a product that contains a polymerization inhibitor instead of a pure product whenever possible. Check for any limitations associated with the inhibitor.
Obtain MSDSs for all possible substitutes. Find out about all of the hazards (health, fire, corrosivity, chemical reactivity) of these materials before making any changes.
Sometimes process changes or modification can improve control of the hazards from working with a dangerously reactive material. These could include the installation of alarms or automatic shut-off switches on equipment to warn of equipment failure, high temperatures or high pressures.
Choose the least hazardous materials and process that can do the job effectively and safely. Learn how to work safely with them, too.
Well designed and maintained ventilation systems remove airborne, dangerously reactive materials from the workplace and reduce their hazards.
The amount and type of ventilation needed depends on such things as the type of job, the kind and amount of materials used, and the size and layout of the work area. An assessment of the specific ways a workplace stores, handles, uses and disposes of its dangerously reactive materials is the best way to find out if existing ventilation controls (and other hazard control methods) are adequate.
Some workplaces may need a complete system of hoods, ducts and fans to provide acceptable ventilation. Others may require a single, well-placed exhaust fan. No special ventilation system may be needed to work with small amounts of dangerously reactive materials which do not give off airborne contaminants.
Make sure ventilation systems for dangerously reactive materials are designed and built so that they do not result in an unintended hazard. Ensure that hoods, ducts, air cleaners and fans are made from materials compatible with the dangerously reactive substance. Systems may require explosion-proof electrical equipment.
Ensure that the system is designed to avoid buildups of dusts or condensation of vapours. The vapours of inhibited liquids are not inhibited. When they condense, the liquid could polymerize or decompose easily.
Keep systems for dangerously reactive materials separate from other systems exhausting incompatible substances. Periodic inspection of ventilation systems will help maintain them in good operating condition.
Store dangerously reactive liquids and solids according to the occupational health and safety regulations and fire and building codes that apply to your workplace. These laws may specify the kinds of storage areas, such as storage rooms and buildings, allowed for different materials. They may also specify how to construct these storage areas, and the amounts of dangerously reactive materials that can be stored in each storage area.
The following provides some general guidelines for storing dangerously reactive liquids and solids safely.
Inspect all incoming containers before storing to ensure that they are undamaged and properly labelled. Do not accept delivery of defective containers.
Store dangerously reactive materials in containers that the chemical supplier recommends. Normally, these are the same containers in which the material was shipped. Repackaging can be dangerous especially if contaminated or incompatible containers are used. For example, strong hydrogen peroxide solutions can decompose explosively if placed in a container with rusty surfaces. Bottles for light-sensitive materials are often made of dark blue or brown glass to protect the contents from light. Containers for water-sensitive compounds should be waterproof and tightly sealed to prevent moisture in the air from reacting with the material.
Make sure containers are suitably labelled. For materials requiring temperature control, the recommended storage temperature range should be plainly marked on the container. It is also a good practice to mark the date that the container was received and the date it was first opened.
Protect containers against impact or other physical damage that might cause shock. Do not use combustible pallets, such as wood, for storing oxidizing materials or organic peroxides.
Normally keep stored containers tightly closed. This helps to avoid contamination of the material or evaporation of solvents used to dilute substances, such as some organic peroxides, to safer concentrations.
Some dangerously reactive liquids, such as strong hydrogen peroxide solutions or certain organic peroxide products, gradually decompose at room temperature and give off gas. These liquids are shipped in containers with specially vented caps. These vent caps relieve the normal buildup of gas pressure that could rupture an unvented container. Check vent caps regularly to ensure that they are working properly. Keep vented containers in the upright position. NEVER stack vented containers on top of each other.
Store dangerously reactive liquids and solids separately away from processing and handling areas and from incompatible materials. Some dangerously reactive materials are incompatible with each other. Do not store these beside each other. Separate storage can minimize personal injury and damage caused by fires, spills or leaks.
Check the reactivity data and storage requirements sections of the MSDS for details about what substances are incompatible with a specific dangerously reactive material.
Construct walls, floors, shelving, and fittings in storage areas from suitable materials. For example, use non-combustible building materials in storage areas for dangerously reactive oxidizers or organic peroxides. Use corrosion-resistant materials for dangerously reactive corrosives.
Ensure that floors in storage areas are watertight and without cracks in which spilled materials can lodge. Contain spills or leaks by storing smaller containers in trays made of compatible materials. For larger containers, such as drums or barrels, provide dikes around storage areas, and sills or ramps at door openings.
Store smaller containers at a convenient height for handling below eye level if possible to reduce the risk of dropping them. Avoid overcrowding in storage areas. Do not store containers in out-of-the-way locations where they could be forgotten.
Store containers away from doors. Although it is convenient to place frequently used materials next to the door, they could cut off the escape route if an emergency occurs.
Store dangerously reactive materials in areas which are:
Store dangerously reactive materials in dry, cool areas, out of direct sunlight, and away from steam pipes, boilers or other heat sources. Follow the chemical supplier's recommendations for maximum and minimum temperatures for storage and handling. Higher temperatures can be hazardous since they can start and speed up hazardous chemical reactions. In many cases, inhibitors can be rapidly depleted at higher-than-recommended storage temperatures. Loss of inhibitor can result in dangerous reactions.
Some dangerously reactive materials must be kept at low temperatures in refrigerators or freezers. Use only approved or specially modified units. These are generally known as "laboratory safe". Standard domestic refrigerators and freezers contain many ignition sources inside the cabinet.
It can also be hazardous to store dangerously reactive materials at less than the recommended temperature. For example, acrylic acid is normally supplied with an inhibitor to prevent polymerization. Acrylic acid freezes at 13?C (55?F). At temperatures less than this, it will partly solidify. The solid part contains little or no inhibitor; the inhibitor remains in the liquid portion. The uninhibited acrylic acid can be safely stored below the freezing point but it may polymerize violently if it is heated to warmer temperatures.
Some organic peroxides are sold dissolved or dispersed in solvents, including water, to make them less shock-sensitive. If these are cooled to below their freezing points, crystals of the pure, very sensitive organic peroxide may be formed.
Alarms that indicate when storage temperatures are higher or lower than required may be needed.
Follow the chemical supplier's directions about inhibitors used in a particular product. Where appropriate, check inhibitor and oxygen levels and add more as needed according to the supplier's instructions.
Do not keep a material for longer than the chemical supplier recommends.
At all times:
Open and dispense containers of dangerously reactive materials in a special room or area outside the storage area. Do not allow any ignition sources in the vicinity. Take care that the dangerously reactive materials do not contact incompatible substances. Use containers and dispensing equipment, such as drum pumps, scoops or spatulas, that the chemical supplier recommends. These items must be made from materials compatible with the chemicals they are used with. Keep them clean to avoid contamination.
When transferring materials from one container to another, avoid spilling material and contaminating your skin or clothing. Spills from open, unstable or breakable containers during material transfer have caused serious accidents.
NEVER transfer liquids by pressurizing their usual shipping containers with air or inert gas. The pressure may damage ordinary drums and barrels. If air is used, it may also create a flammable atmosphere inside containers of flammable or combustible liquids.
Glass containers with screw-cap lids or glass stoppers may not be acceptable for friction-sensitive materials. Avoid using ordinary screw-cap bottles with a cardboard liner in the cap for moisture-sensitive chemicals. Airborne moisture can diffuse slowly but steadily through the liner. NEVER transfer materials stored in a vented container into a tightly-sealed, non-vented container. The buildup of gas pressure could rupture it.
Dispense from only one container at a time. Finish dispensing and labelling one material before starting to dispense another. Dispense the smallest amount possible, preferably only enough for immediate use.
Keep containers closed after dispensing to reduce the risk of contaminating their contents.
NEVER return any unused material, even if it does not seem to be contaminated, to the original container.
If a dangerously reactive material freezes, do not chip or grind it to break up lumps, or heat it to thaw it out. Follow the chemical supplier's advice.
Avoid dropping, sliding or skidding heavy metal containers such as drums or barrels of friction- or shock-sensitive material.
Make sure that all areas where dangerously reactive liquids and solids are used are clean and free of incompatible materials and ignition sources. Do not allow temperatures in these areas to become hot enough to cause a hazardous reaction.
Regular workplace inspections can help to spot situations in which dangerously reactive materials are stored, handled or used in potentially hazardous ways.
Following these basic safe practices will help protect you from the hazards of dangerously reactive liquids and solids:
Ensure that processing equipment is clean, properly designed and made from materials compatible with the dangerously reactive material used. Find out from the chemical supplier what materials are suitable for the specific chemical. For example, some steels and aluminum alloys, zinc and galvanized metal can cause rapid decomposition of certain organic peroxides.
Accidents have happened when reactive materials came in contact with incompatible heat exchange fluids or fluids used in instruments to monitor processes.
Reactive substances have, on occasion, leaked and soaked into equipment insulating materials. Insulators have good heat-keeping ability. Once a reaction begins within the insulating material, the heat given off from the reaction can rapidly build up to hazardous levels and may result in fire.
Some jobs require that dangerously reactive materials be diluted prior to use. Always strictly follow the chemical supplier's advice. Using the wrong solvent or a contaminated solvent could cause an explosion. Using reclaimed solvents of unknown purity can be hazardous. They might contain dangerous concentrations of contaminants that are incompatible with the dangerously reactive material.
Some operations involving dangerously reactive materials can be especially hazardous. Many accidents have occurred during distillation, extraction or crystallization because these processes involve concentrating reactive substances. Sieving dry, unstable materials might result in static electricity sparks which could cause ignition.
Filtering friction- or shock-sensitive chemicals with materials and devices that produce frictional heat, such as sintered glass filters, can be hazardous.
Before using a new material in an operation, find out as much as possible about the potential hazards of the particular chemical and operation.
Dangerously reactive wastes are hazardous. Dispose of unwanted or contaminated reactive chemicals promptly using a method the chemical supplier recommends. Consider any reactive materials accidentally mixed with an unknown or foreign material as contaminated, and dispose of them. NEVER attempt to salvage spilled or contaminated dangerously reactive materials.
"Empty" drums, bottles, bags and other containers usually contain hazardous residues. NEVER use these "empty" containers for anything else, no matter how clean they seem to be. Treat them as dangerously reactive wastes. Follow the chemical supplier's advice for safely handling or decontaminating "empty" containers.
Store reactive waste in the same way as unused dangerously reactive materials. Use only compatible containers for wastes. Identify their contents with suitable labels.
NEVER dispose of these wastes in ordinary garbage or down sinks or drains. Dispose of them according to the supplier's advice, or through hazardous waste collection and disposal companies. In all cases, dispose of dangerously reactive wastes according to the environmental laws that apply to your jurisdiction. Contact the appropriate environmental officials for details.
Maintain good housekeeping at all times in the workplace:
*Note: For example, some commercial sorbent materials used for spill clean-up may initiate polymerization in some monomers. Do not use sawdust or other combustible sweeping compounds to clean up spills of oxidizers or organic peroxides.
Personal cleanliness helps protect people working with dangerously reactive materials:
Regular equipment maintenance can prevent hazardous conditions in the workplace:
If other methods, such as engineering controls, are not available or effective in controlling exposure to dangerously reactive materials, wear suitable personal protective equipment (PPE). Choosing the right PPE for a particular job is essential. MSDSs should provide general guidance. Also obtain help from someone who knows how to evaluate the hazards of a specific job and how to select the proper PPE.
When using materials that are harmful by skin contact, wear protective gloves, aprons, boots, hoods or other clothing depending on the risk of skin contact. Choose clothing made of materials that resist penetration or damage by the chemical. The MSDS should recommend appropriate materials. If it does not, contact the chemical supplier for specific information.
Always wear eye protection when working with dangerously reactive chemicals. Avoid ordinary safety glasses. Use chemical safety goggles instead. In some cases, you should also wear a face shield to protect your face from splashes. The current Canadian Standards Association (CSA) Standard Z94.3, "Industrial Eye and Face Protectors," provides advice on selection and use of eye and face protectors.
If respirators must be used for breathing protection, there should be a written respiratory protection program to follow. The current CSA Standard Z94.4, "Selection, Care, and Use of Respirators," gives guidance for developing a program. Follow all legal requirements for respirator use and approvals. These may vary between jurisdictions in Canada.
Sorbents in respirator cartridges or canisters must be compatible with the chemical they are supposed to protect against. For example, oxidizable sorbents such as activated charcoal, may not be acceptable if high airborne concentrations of oxidizers or organic peroxides are present. A hazardous reaction might occur.
Know and be familiar with the right PPE for emergencies, as well as normal operations.
Wear the PPE needed for doing a particular job. It cannot provide protection if it is not worn.
Act fast in emergencies like chemical leaks, spills and fires:
Only specially trained and properly equipped people should handle the emergency. Nobody else should go near the area until it is declared safe.
Planning, training and practicing for emergencies help people to know what they must do. Prepare a written emergency plan. Update it whenever conditions in the workplace change.
The MSDSs for the materials used are a starting point for drawing up an emergency plan. MSDSs have specific sections on spill clean-up procedures, first aid instructions, and fire and explosion hazards, including suitable fire extinguishing equipment and methods. If the directions in each MSDS section are not clear or seem incomplete, contact the material's supplier for help.
It is very important to know the best ways to fight fires involving dangerously reactive materials. For example, using water on water-reactive chemicals can cause the rapid release of lethal gas or, in some cases, violent explosions.
There are numerous other sources to turn to for help in developing your emergency plans. The local fire department can provide assistance in this area, as well as training. You can also obtain useful information at little or no cost from environmental and health and safety enforcement agencies, provincial accident prevention associations, St. John Ambulance, insurance companies, occupational health and safety groups, unions, professional associations, certain colleges and universities, and CCOHS. Private consultants who specialize in these matters are also available.
Document last updated on December 3, 2003