Repeated or prolonged exposure to common solvent components such as toluene, benzene, and trichloroethane can have profoundly bad effects on your health. All are carcinogens and can be absorbed through your lungs or through your skin. During a shutdown, you commonly see gasoline-powered equipment such as a generator used for lights and power. Toluene and benzene are also in gasoline.
Fuels and solvents aren’t the only sources of harmful vapors; for example, battery rooms need ventilation not just to prevent an explosion but also to protect the eyes, skin, and lungs of workers in those rooms.
Vapors aren’t the only type of hazard that can be mitigated with ventilation. Dust and fibers also present ventilation hurdles; a cheap K95 respirator (if properly fitted) can provide protection. However, with vapors, you must either ventilate or wear significant personal protective equipment. To protect your lungs, you might wear a charcoal canister respirator or an air-supplied one; this won’t, however, protect your skin or eliminate an explosion hazard. Ventilation is your first defense.
Ensure proper ventilation
Before using a product, you must answer the question, “How much ventilation is enough?” If the label says adequate ventilation, that doesn’t help you very much. A flow specification (e.g., cubic feet per minute) should be on the material safety data sheet. If not, you can probably do an Internet search to find the answer for a particular gas. However, if the product is a mix (and they usually are), you may need to contact the manufacturer directly.
With some items, common sense applies. For example, you have a can of spray paint and intend to touch up an enclosure before installing it (now that all the holes are drilled in it). You could spray the paint while near an open door with a fan running just on the other side to pull the fumes outside. Or if you need to fill a generator with fuel, take it outside to fill it up and bring it back in when done. No ventilation spec is needed. Also, by setting up the ventilation ahead of time and particularly in this way, you get zero exposure and zero combustibles density in the work area.
Another factor: you might not be using any harmful product yet still be exposed. This often happens when another crew (typically a different trade) is working in your building. They can be 50 ft away, perhaps using spray paint to touch up a gearbox they just rebuilt — and you end up breathing in the paint solvents. In cases like these, you need to:
- Stop work.
- Communicate with the other crew the problem they are causing.
- Propose a solution.
- Do the previous steps with respect and perhaps a little humor.
If they refuse to adequately ventilate, let them know they are stopping you from doing your assigned work. Then report them to the nearest supervisor if you cannot readily contact yours.
Leaks and spills
Ventilation may be needed under circumstances other than intentional use of a product, such as a leak in process piping or a spill. In such a case, you might be tempted to immediately ventilate. However, if a combustible gas or dust has been released, will the ventilation supply the oxygen part of the fuel + oxygen + ignition = fire equation? You need to know what chemicals might accidentally be released and what your expected response is before you enter the area.
Typically, unless you are on the plant’s spill response team, the expected response is:
- If you can quickly shut off a supply valve or take similar action, do so. Do not attempt to clean up the spill.
- Leave the area; warn others on your way out.
- Notify the spill response team or, if you cannot do that directly, notify a supervisor for the area.
- Notify your supervisor.
You’ll notice the preceding list doesn’t include anything about ventilation. That’s because the goal is to get people out of danger as quickly as possible.
Again, common sense must come into play. For example, that fella who is filling up a generator indoors accidentally slips with the gas can and spills a pint of gas on the floor. You know that nobody is going to pass out from the gasoline fumes, but you also know that a high concentration of them is dangerous. Think of what might happen if a 400A breaker trips under load at this time!
Immediately opening a door for ventilation would be a good first action. It also would be prudent to rope off the area until it is fully ventilated. You would still need to warn others nearby that there’s been a gas spill, and report the incident.
NFPA 70E says you need to have “awareness and self-discipline” when working in the presence of electrical hazards [110.5(D)]. This is also a good mindset for working anywhere that chemical hazards might be present, whether by the deliberate use of a chemical or due to a possible spill. If you have this mindset, you’re going to set up the ventilation ahead of time rather than wait for things to get dicey.
