Hazardous Materials Safety

Knowing what a chemical can do is only half the job. You also have to handle it, store it and clean it up without getting hurt. Cleaners in a hospital, solvents in a shop, fuels on a site and acids in a plant all follow the same basic rules. Most harm comes from a few simple failures: the wrong glove, two products mixed together, a leaking container stored next to the wrong neighbor, or a spill that someone tackled without knowing what it was. Your employer's procedures and the Safety Data Sheet (SDS) for each product always come first.

What You Will Be Able to Do

• Explain what exposure limits mean, including what they do not promise.
• Choose chemical gloves and know when a respirator is needed.
• Store flammable liquids within limits, and keep incompatibles apart.
• Respond correctly to a small spill, and know when to get out instead.
• Decontaminate yourself and use an eyewash.

Before You Handle a Chemical

Check the label, then the SDS. Section 7 covers handling and storage, Section 8 covers exposure limits and PPE, and Section 10 tells you what the chemical reacts with. Then look at the job. How much will you use? For how long? Is there ventilation? What happens if you spill it?

Chemicals reach your body by being breathed in, absorbed through the skin, or swallowed. The last often happens through dirty hands on food or cigarettes. Effects vary too. A corrosive destroys tissue on contact, and the damage can be permanent. An irritant causes redness or swelling that heals once the exposure ends.

Exposure Limits

A PEL is a legal limit on the airborne level over a work shift. It is not a promise that nobody will be harmed below it. Many PELs date from decades ago, and OSHA itself says many are out of date, so TLVs and RELs are often lower. Treat the lowest limit on the SDS as your goal.

Worked example: A worker is exposed to a solvent at 200 ppm for 2 hours and 50 ppm for 6 hours. The PEL is 100 ppm as an 8-hour average.

1. Multiply each level by its hours: 200 x 2 = 400, and 50 x 6 = 300.
2. Add them: 400 + 300 = 700.
3. Divide by 8 hours: 700 / 8 = 87.5 ppm.

The average is under the PEL, but those 2 hours may still break a short-term limit, so check that as well.

Protecting Yourself

Start with the top of the hierarchy of controls: a safer product, closed systems, or local exhaust ventilation. PPE covers what is left.

Respirators are needed when engineering and work practice controls cannot bring exposure below the limit, and during some emergencies. The type depends on the chemical, how much is in the air and the oxygen level. Only supplied-air respirators or self-contained breathing apparatus (SCBA) are adequate in IDLH conditions. Using a respirator requires a medical evaluation, a fit test and training.

Gloves must match the chemical. Nothing protects against everything. Breakthrough time tells you how long a chemical takes to get through the material, so check the SDS or the maker's chart for your product.

Inspect gloves before use, and replace them when they swell, crack, stiffen or change color.

Storing Flammable Liquids

A liquid's flash point is the lowest temperature where it gives off enough vapor to catch fire. If the flash point is below room temperature, the liquid is making ignitable vapor right now, on the bench in front of you. It is the vapor that burns.

You may see two systems. NFPA 30 and many labels call a liquid flammable if its flash point is below 100°F, and combustible if it is at or above 100°F. OSHA's rule, 29 CFR 1910.106, now uses Categories 1 to 4 and covers liquids up to a flash point of 199.4°F.

General industry storage limits in 1910.106 include:

• In a cabinet: up to 60 gallons of Category 1, 2 and 3 liquids, or up to 120 gallons of Category 4.
• Outside a cabinet or storage room, in one fire area, at a plant where flammable liquids are only incidental to the main business: up to 25 gallons of Category 1 in containers, and up to 120 gallons of Category 2, 3 and 4 in containers.

Chemical plants, refineries and distilleries fall under other parts of the rule. Construction has its own limits in 29 CFR 1926.152, and fire codes can be stricter. Use only approved containers and safety cans. Keep lids closed. Keep liquids away from ignition sources.

Pouring flammable liquid can build a static charge. When you move it between metal containers, bond them together and ground the supply container, so that a spark cannot jump.

Warning: Vapors from flammable liquids are usually heavier than air. They can flow along the floor to a pilot light or heater well away from the container.

Keeping Incompatibles Apart

Sealed containers still leak, sweat vapor and get knocked over. Store by hazard type, not by alphabet.

Oxidizers supply oxygen, which is why they can make a small fire worse or start one in material that would not usually ignite. Use separate shelves and spill trays, and do not store heavy or corrosive containers above eye level.

Never mix cleaning products or pour one chemical into a tank or bucket that held another until you have checked both SDSs. If you think two chemicals are about to meet, stop the work, move people away, and check before anyone continues.

Responding to a Spill

The first question is whether you should touch it at all.

Small Spill

1. Alert people nearby, and keep others away.
2. Check the SDS, Sections 6 and 8.
3. Put on the PPE that the SDS calls for, before you approach.
4. Contain the spill with absorbent socks or pads, and protect drains.
5. Absorb it with a material suited to that chemical.
6. Collect the waste into a labeled, compatible container.
7. Clean the area, and decontaminate your tools and yourself.
8. Dispose of it as hazardous waste, following your procedure.
9. Report what happened and restock the spill kit.

Large Spill

1. Evacuate the area right away, and warn others.
2. Move upwind and uphill if you are outdoors.
3. Call your emergency number or 911, and sound the alarm if needed.
4. Keep people out, and account for your crew.
5. Give responders the SDS and tell them what you know.

Only workers trained under OSHA's emergency response rule, 29 CFR 1910.120 (HAZWOPER), may handle an emergency release.

Waste

Hazardous waste goes in the designated container, with a label, a closed lid and the right contents. It never goes down a drain or in regular trash. Do not mix waste streams unless your procedure says to, because mixing can cause a reaction and can make the waste much harder to treat. Federal hazardous waste rules and state programs set how it is stored and shipped.

Decontamination and First Aid

Before a break or leaving the area:

1. Remove PPE in the right order, without touching the outside of gloves with bare skin.
2. Wash hands, face and exposed skin with soap and water.
3. Change out of contaminated clothing, and do not take it home.
4. Do not eat, drink, smoke or use your phone until you have washed.

If a chemical gets on you, flush the skin with water, and remove contaminated clothing. If it gets in your eyes, go to the eyewash right away, hold your eyelids open, take out contact lenses if you can, and flush for at least 15 minutes. Then get medical care, and bring the SDS.

OSHA's rule, 29 CFR 1910.151(c), requires suitable quick-drench facilities where corrosive materials are used. The details come from the consensus standard ANSI Z358.1:

• Reachable within 10 seconds, about 55 feet, with a clear path on the same level.
• Eyewash flow of at least 0.4 gallons per minute for 15 minutes.
• Safety shower flow of at least 20 gallons per minute for 15 minutes.
• Tepid water, between 60°F and 100°F.
• Plumbed units activated weekly.

Know where yours is before you need it, because you may be finding it with your eyes shut.

Common Mistakes

Check Your Understanding

1. A cleaner plans to pour an acid-based toilet cleaner into a bucket that still has bleach in it. What should you do?

Stop her. Together they can give off chlorine gas. Keep the two apart, move people away, and check both SDSs.

2. A quart of a known solvent tips over on your bench. You are trained, and the kit is nearby. What comes before you touch it?

Alert others, check the SDS, and put on the PPE it calls for.

3. A drum splits and fills the room with fumes. Nobody knows what is in it. What do you do?

Evacuate, warn others, call for help and keep people out. Do not attempt cleanup.

4. Your exposure was 90 ppm as an 8-hour average, and the PEL is 100 ppm. The TLV is 50 ppm. Are you fine?

You are within the legal limit, but above the recommended limit. Raise it, and look for ways to reduce the exposure.

Key Takeaways

• A PEL is a legal limit, not a guarantee of safety.
• Use controls first, and match gloves and respirators to the chemical.
• Only supplied air or SCBA works in IDLH conditions.
• Know the storage limits for flammable liquids, and bond and ground when you pour.
• Keep incompatibles apart, because sealed containers still leak.
• For a small spill, check the SDS and put on PPE before you approach. For a big one, get out.
• Flush eyes for 15 minutes, and wash before you eat or drink.