We all know how important it is to take precautions when working with hazardous materials. But we may not always recognize that it's equally important to maintain the same high level of safety when these materials are in storage.
Even when hazardous materials are out of sight in containers, they should never be out of mind. If they're stored properly, these substances shouldn't cause problems. But unless we're all aware of what safe storage means, and how to protect ourselves in a storage area, we run the risk of accidents. And we can't afford to take that risk with hazardous materials. So today we're going to discuss the basics of safe hazardous materials storage and the precautions we should follow when we're in those areas. We'll also look more closely at some specific high-risk substances so that you can better understand why we store these materials as we do.
The Occupational Safety and Health Administration has detailed rules for the location and construction of rooms or buildings that contain these substances, including explanations of what can't be stored with different types of hazardous materials. As you realize that every aspect of storage room design has a reason and purpose, you'll be better able to help us see to it that those storage areas – and the substances stored in them – are kept safe.
The substances we use and store can, as you know, pose a number of different hazards if they're not handled and used properly and safely.
Some of the hazards are physical hazards. These could include:
- Sudden release of pressure (for instance, if a tank of compressed gas is punctured)
- Reactivity (fire, explosion, or release of dangerous gases that can result from contact between particular chemicals and certain other chemicals or air or water)
There are also many potential health hazards that can result from overexposure to a hazardous substance. Sometimes the hazard is minor, like a headache or mild skin rash. But other health hazards are much more serious. For instance, you could get skin burns from contact with corrosive chemicals. With some substances, too much exposure – or prolonged exposure – could cause organ damage, allergic-type reactions, cancer or, in the worst and most rare cases, death.
Sometimes the risk isn't just to the individuals working with or near the substance in question. A major spill of a chemical that's dangerous to health can pose dangers to many people if it gets into the water supply. If there's a fire or explosion that releases toxic gases, they could spread out to harm people in the neighborhood.
So there are a lot of potential risks – including some very serious ones – in any hazardous materials storage area. Fortunately, there are also a lot of excellent safeguards against those risks becoming realities. Our storage areas are designed for safety and maintained for safety. That's only good sense, and in many instances, it's also the law.
A number of different OSHA regulations include requirements for hazardous materials storage. Most of these regulations deal with specific substances, such as liquefied hydrogen, or with specific groups of substances such as flammable and combustible liquids.
But OSHA also has a materials handling regulation (29 CFR 1910.176) that covers general safety requirements for storage areas – no matter what's kept there. This regulation requires us to keep aisles and passageways clear and in good repair, with no obstructions that could cause hazards. It also states that "storage of materials shall not create a hazard." To OSHA, this means that containers should be placed carefully in tiers that are "stacked, blocked, interlocked and limited in height so that they are stable and secure against sliding or collapse."
In addition, the regulation states, "Storage areas shall be kept free from accumulation of materials that constitute hazards from tripping, fire, explosion or pest harborage." As we mentioned, OSHA also has regulations that detail where and how a wide variety of substances can be stored, including liquefied hydrogen (1910.103), bulk oxygen (1910.104), and explosives and blasting agents (1910.109). We'll discuss some of OSHA's requirements for some of these substances today so that you'll get a clearer idea of why we store things the way we do and what types of principles we're following.
As you know, no hazardous substance can sneak into your facility. All of them are carefully labeled and identified as hazardous. And they also have material safety data sheets (MSDS) that explain their hazards in detail, along with the measures we can take to protect ourselves from these hazards. You should, of course, always check both labels and MSDS before starting any job involving hazardous materials. Then you should follow the precautions they contain, such as wearing protective clothing and equipment. This same precaution applies to placing materials in storage or removing them for use or transport. Container labels generally alert you to key hazards. They tell you if a substance could burn or explode, for instance. Some labels have more detailed information, and you should always check labels carefully.
When it comes to storage, the MSDS contains a lot of vital information you need to know before you can put away or remove a container that holds a hazardous substance. Here are some MSDS sections that you should always check before working in a hazardous substance storage area:
Physical and chemical characteristics: In this section, you'll find the boiling point and melting point. They let you know when the substance could change form, as from a liquid to a breathable gas. Also, here are vapor pressure, vapor density and evaporation rate, which warn about how fast or easily the chemical evaporates or releases vapors that could be dangerous to inhale. Solubility in water and specific gravity let you know if the substance will dissolve or sink in water, which could be crucial if there's a spill that puts water supplies at risk. This MSDS section also tells you the substance's normal appearance and odor, which you have to know before you can recognize that anything's wrong.
Fire and explosion hazard data: This section is particularly important in storage situations. You have to be sure that hazardous materials aren't exposed to temperatures at which they could ignite (flammability limits) or explode (explosive limits). This section also gives you the flash point – the temperature at which flammable liquid vapors could catch fire if they contact an ignition source.
Reactivity: This section needs careful study when you're concerned with storage. Pay particular attention to what the MSDS says about incompatibility. If exposing this substance to a particular other substance could cause a hazardous reaction, you want to be sure those incompatible substances are not stored anywhere near each other. Some substances are also incompatible with air or water. You also want to check this section to find out whether the substance is stable or unstable and what temperature, pressure, etc., could cause it to change or disintegrate.
Health hazard data: It is just what it sounds like. In this section, you learn whether the risk to your health comes from inhaling, swallowing, or skin contact with the substance. You also find out what the specific health risks can be, including cancer. This information is important not just to people in the vicinity of the container, but anyone who could be affected if the substance somehow gets into the air or the water supply.
Protection against hazards
Container labels and material safety data sheets help you to identify the hazards. Our organization's safety procedures, including those required by OSHA, help you to work safely with and around those hazards.
We're protected from the hazards of stored substances in a variety of ways. They include:
- The design of storage buildings and areas and the materials used in their construction
- Drainage, dikes and other means of keeping spills from spreading into the water supply
- Keeping hazardous substances separated from anything that could trigger the hazard – for instance, keeping flammable liquids away from flames or other ignition sources
- Storage and handling rules, such as how to stack and remove containers
- Emergency equipment availability, such as fire extinguishers and spill clean-up materials
- Personal protective clothing and equipment
- Good housekeeping practices
Not all of these safety elements are your responsibility. But it's important that you understand why storage areas are set up the way they are. They're designed and organized for safety, and it's up to you to help us keep them that way, and report anything you know or think might not be right.
Flammable and combustible liquids (1910.106)
Let's look for a minute at some of the OSHA requirements for storing flammable and combustible liquids – liquids that could burn. OSHA’s very long, detailed regulation divides these liquids into a number of classes based on their boiling point and flash point. Those that could burn at lower temperatures obviously need even more precautions than the others. For example, OSHA’s regulation says that above-ground tanks for these liquids should be at least 3 feet apart, with some variations depending on what substance and what quantity the container holds. These tanks also have to have diking or drainage to prevent a liquid spill from getting into the ground or water supplies.
If flammable or combustible liquids are stored in buildings, OSHA wants to reduce the chance that the floor will settle unevenly or that the containers will corrode. Thus, the regulation requires storing these containers on the ground or on concrete, masonry piling or steel foundations. Some smaller quantities of flammable or combustible liquids can be stored in buildings used for other purposes. But even where that's permitted, the inside storage rooms have to meet standards for fire resistance and have adequate venting. In addition, the containers that hold these liquids must be separated from other areas of the building by fire walls and kept away from exits, stairways, etc.
Flammable or combustible liquids are stored in tanks or closed containers, which must be made of metal and have emergency vents. In some cases, small quantities can be kept in containers inside storage cabinets. But those cabinets must also be fire resistant and have large clear lettering that says FLAMMABLE – KEEP FIRE AWAY. Even when these burnable liquids are stored in their own separate buildings, OSHA requires very careful storage procedures. The safety agency recommends storing containers on pallets or something similar to keep them stable. In addition, aisles in the storage area must be at least 3 feet wide to allow fire equipment to get through.
OSHA also requires that when you stack containers, you make sure they're no closer than 3 feet to beams, girders, sprinklers or other overhead fixtures. In general, it's a good idea to stack drums on racks rather than just on top of each other. That way, you can identify and get to them more easily. Drums that contain flammable liquids have to be grounded, as do the racks that hold them.
Since all these measures are designed to prevent fires, OSHA also sensibly requires that no open flames or smoking be permitted in the storage area. The containers also have to be kept away from cutting, welding, hot surfaces and any other possible ignition source.
There's a particular risk when you transfer a flammable or combustible liquid from one container to another. So OSHA requires those tasks to be done in an area that's separated from other operations either by fire-resistant construction or adequate distance. Ventilation, drainage, and fire extinguishers are also needed in these areas.
Liquefied hydrogen (1910.103)
To emphasize how important proper storage is, let's look briefly at OSHA’s requirements for a couple of other substances. To reduce the risk of fire with liquefied hydrogen, for instance, OSHA’s regulation specifies the maximum quantities of the substance you must or can store outdoors, in a special building, in a separate room, etc.
If liquefied hydrogen is stored outdoors, the storage site has to be fenced and posted with signs to keep unauthorized personnel out. Signs also have to identify what's stored there as:
“Liquefied Hydrogen – Flammable Gas – No Smoking – No Open Flames”
Liquefied hydrogen storage has to be located so that it's not exposed to electric power lines or lines that carry flammable liquids or gases or oxidizing materials. If stored indoors, vent safety relief devices must be located at least 25 feet above grade, with a clear route to a safe location outdoors. You can store smaller quantities of liquefied hydrogen in an indoor area that's not separated from other storage or operations. But even in these cases, the containers have to be at least 20 feet from flammable liquids and readily combustible materials, 35 feet from electrical equipment or concentrations of people, and 50 feet from ventilation intakes or flammable or oxidizing gases.
No matter where they're kept, the containers have to be stored upright and firmly secured.
Bulk oxygen (1910.104)
Similar precautions are contained in OSHA’s regulation for bulk oxygen. It can be stored outdoors or in a special non-combustible vented building. In either case, it can't be exposed to electrical power lines or flammable or combustible liquid or flammable gas lines.
Unless there are fire walls between bulk oxygen storage and conditions that could cause special fire hazards, you also have to be sure the bulk oxygen is stored at least 50 feet from combustible structures or highly combustible solid materials and 35 feet from materials that burn slowly or congested areas like locker rooms or lunch rooms.
This review gives you an idea of the kinds of precautions needed just to select a storage place for hazardous substances and place the substances within it. We hope it makes clear that substances can be hazardous even when they're contained. There's always the risk that they'll somehow escape from those containers or be exposed to conditions that will overwhelm inadequate precautions.
So it probably won't surprise you to know that anyone who goes into a hazardous materials storage area has to take precautions, too.
First is the precaution we've already covered: Read container labels so you know what hazards you could be facing. If you are going to use or handle the container or its contents, read and follow the material safety data sheet, too. It's also important to pay close attention to any and all signs outside or inside the area. If a sign restricts entry to authorized personnel and you're not authorized, stay out. There's a reason for it. If the signs warn you about fire risks:
- Don’t smoke in or near the area.
- Don't use sparking tools or anything that could ignite the hazardous substance itself or anything combustible in the area.
- Check that fire extinguishers are available and ready for use.
You'll probably need to use some type of personal protective clothing and equipment if you're working in a hazardous materials storage area. Your reading of the MSDS should help you determine what types of gloves, clothing, eyewear, etc., will protect you from the risks of these particular substances. As you know, the same PPE won't protect you from every hazard, so it's important to make the right selection. And, as always, if in doubt, ASK!
Also, do your part to make sure that the storage area is kept neat and orderly and doesn't add to the potential hazards. That includes keeping the aisles clear, the floors clean, and picking up trash. If the storage area holds flammable or combustible substances, it's particularly important to keep combustible trash to a minimum and place it in covered metal containers for disposal. Those containers should be emptied, and the contents properly disposed of daily.
Pay attention to the containers themselves. If you notice holes, leaks, any sign of rust or rot, or any indication that the container is in less than perfect shape, report it immediately. If a container is missing a label or the label is so torn or faded that you can't read it, report it immediately. Keep in mind that those containers are the only thing between their hazardous materials and you. We want to be sure they're in top condition.
Storage rooms should have decent lighting, too, so you can see what the substances are and read the labels. If the lighting is not adequate, or if bulbs are burned out, report it immediately.
Finally, if you or anyone else in a storage area is accidentally exposed to a hazardous substance, get out immediately. The exposed person must have at least first-aid attention. If in doubt about what to do, contact your supervisor or the emergency coordinator.
This article should have given you a good picture of why our hazardous materials storage areas are located where they are and set up as they are. And, we hope you recognize that storing materials, no matter how properly and carefully, doesn't eliminate their hazards.
When you approach or work in a storage area, you have to take all the precautions you would at your own workstation. Use the information on labels and MSDS. Keep things neat and clean. Obey the instructions on signs. Wear the right protective clothing. In other words, practice all the safety procedures you've learned for any work that involves hazardous substances. As you know, hazardous substances do pose hazards. But you shouldn't have to worry about those hazards if you use the information available to protect yourself and everyone else in the vicinity of this facility.
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