By Robert Hand, Hazardous Material Program Manager, City of Raleigh Fire Dept.
As an instructor teaching all levels of hazmat courses and hazmat continuing education, to both public and private organizations, I have heard the comment, “I don’t like hazmat.” While I can understand the comment to some degree, I do not understand the mindset. So, you don’t like hazmat? There is one very important thing that does not care if you like hazmat or not, and that is the chemicals you may come in contact with.
Chemicals for the most part treat every individual the same, regardless of what your opinion of them is, or if you enjoyed that hazmat course. Most of us in public safety swore an oath to protect the public, property, and the environment. This author does not enjoy emergency medical calls. I could spend the rest of my career and never have to run another EMS call and would walk out to retirement just as happy, but then that oath shows up. I was blessed to join an organization that allowed me to do what I enjoyed the most, fighting fires and later growing into the hazardous materials realm. This organization is also in the emergency medicine business. Based on the organization’s goals and the oath that I swore, it is my job to understand and know what to do for emergency medical calls, regardless of if I enjoy them or not. Knowing medical protocols, what line to pull, or how to use an emergency response guidebook is all part of doing your job, and honoring your oath. I don’t remember “If I like it” at the end of our oath.
Now as a member of a Hazardous Materials Team, I don’t expect that the same level of zeal for hazmat is in every member of public safety. Ponder this fact, being assigned to a hazmat company, when we were dispatched, we always knew we were going to a hazmat incident. This means for the individuals on the Engine, Ladder, EMS unit, or Law Enforcement, has a good chance of responding to an incident and finding out that they are in the middle of a hazmat incident. This just means the individuals that “Don’t like hazmat” are the ones that will discover it first, while the individuals that like hazmat will have time to plan for it most of the time. Remember, that chemical is going to treat them both the same way.
So, what is safe?
If you don’t like hazmat, at least have the ability to determine what is safe. Would you consider Chlorine gas unsafe? What about Ammonia, Mustard Gas, maybe even VX, unsafe? Of course, you would, but why? Have you ever been exposed to any of these gases or chemicals in large amounts? I would hope not, but human beings, despite what we see in our fire stations, sometimes are incredibly capable of learning from the experiences of other humans. At some point in time, a caveman ate something that made him keel over and die. All the other cavemen started telling others about Igor’s experience and learned from it.
It’s great that we can learn from others and know that Chlorine and Ammonia are not chemicals we want to play with, but what if we have never heard of the chemical or can’t even say it. What if you respond to a leaking drum of Tetramethylammonium hydroxide? Where do we pull our experience from? We don’t have any, so we have to look somewhere else to help us understand what is safe.
The first step is finding the Safety Data Sheet (SDS). There are two things I am looking for on the SDS. The first is the Vapor Pressure. When we think of Vapor Pressure, we should think of vapor production. The most important thing to remember to give us a frame of reference is the 2, 20, 200 rule. Diesel has a vapor pressure of 2mm/Hg, Water has a vapor pressure of 20mm/Hg, and Gasoline has a vapor pressure of 200 mm/Hg. If our chemical in question has a high vapor pressure, say 400 mm/Hg, we now understand that this chemical is going to be producing a lot of gases that we could potentially breathe in. If our chemical has a low vapor pressure, say 1mm/Hg we know that this chemical wants to stay a liquid and does not have much vapor production.
The second clue I want is the Short Time Exposure Limit Time Weighted Average (TWA). The time-weighted average is the amount of chemical your employer can legally expose you to in an eight-hour day, 40-hour workweek. I understand that you are not going to be in the area of this unknown chemical for 40 hours, but it provides the frame of reference we need. Chlorine has a TWA of 0.5 Parts Per Million (PPM), while Ammonia has a TWA of 25 PPM, both very low numbers. If our chemical had a TWA of 5,000 PPM, would that help you determine if it was safe? Maybe.
We need to use these numbers together. If I know nothing about Tetramethylammonium hydroxide, but I can see that it has a very low vapor pressure of .5 mm/Hg, and a very high TWA of 10,000 PPM, then I can predict that if I don’t come in contact with the product it is relatively safe. If the SDS showed me that this chemical had a very high vapor pressure of 600 mm/Hg, and a very low TWA of .5 PPM, then I can predict that this chemical is going to produce plenty of gas and it does not take much of the gas to hurt me.
Remember, the number one thing we can do in the presence of unknown chemicals is to use our respiratory protection and avoid contact. Learn the basics of hazardous materials, and know-how to find and understand the information available. Remember the oath we took to protect the public, whether we like it or not, and don’t worry about that drum leaking Tetramethylammonium hydroxide, it’s just an industrial glass cleaner.
Robert Hand is a Captain and Hazardous Material Program Manager of the City of Raleigh Fire Department and Team Leader of the North Carolina Regional Response Team 4. He is a Credentialed Fire Officer by the Center for Public Safety Excellence and holds a Bachelor’s in Fire Administration from Columbia Southern University. He is a fifteen-year veteran of the Raleigh Fire Department and is assigned to the Professional Development Division. He is appointed to the Hazardous Materials subcommittee of the State Emergency Response Committee (SERC) and is the Central Branch Manager for the North Carolina Association of Hazardous Materials Responders.
