What lies between you and a toxic chemical?


CarolinaFireJournal - Glenn Clapp
Glenn Clapp CHMM, CFPS
07/25/2010 -

Hazardous materials personal protective equipment (PPE) is one component of the hazmat response that is often taken for granted. Civilians, for instance, think that a fully encapsulating vapor protective suit (often referred to as a “moon suit” by persons not in emergency services) is a veritable suit of armor that will protect responders against any chemical threat. We as Hazardous Materials Technicians should know that is not the case, however do we know as much as we really need to about our PPE? In addition, do we train as much as we should on PPE and receive as much “suit time” as we should on a regular basis? And think carefully about this one - Is there such a thing as a “Level A” hazmat suit? We will encounter each of these topics as we journey through the following article.


We learn about the basic types of hazmat PPE in Awareness and Operations Level Classes. In terms of chemical protective clothing (CPC) ensembles, the National Fire Protection Association (NFPA) delineates two categories; vapor-protective and liquid splash-protective ensembles. A vapor-protective ensemble consists of a fully-encapsulating suit that is vapor tight and also provides splash protection. A liquid splash-protective ensemble does just that-provides protection against liquid splashes. As can be seen, the NFPA categorization centers around the hazmat suit itself.

The Environmental Protection Agency (EPA) divides hazmat PPE into four levels of protection, which are based on the combination of the suit and related accessories; and the level of respiratory protection. The EPA levels of protection are as follows:

Level A - Fully-encapsulated vapor-protective suit (including accessories) coupled with the highest level of respiratory protection (a self-contained breathing apparatus [SCBA] or supplied air respirator [SAR] with escape SCBA).

Level B - Liquid splash-protective suit (including accessories) coupled with an SCBA or SAR. The suit may be fully-encapsulating or non-encapsulating.

Level C - Liquid splash-protective suit (including accessories) coupled with a lesser level of respiratory protection (an air-purifying respirator or APR).

Level D - A work uniform with associated accessories (offers minimal chemical protection) 

Note: When the EPA states “SCBA” or “SAR”, it is required that the unit be of the positive-pressure type.

The relative level of protection increases in descending alphabetical order from Level D to Level A. As the level of protection increases, however, so does the burden the CPC places on the user (as anyone who has worn a Level A ensemble in a 90 degree, 70 percent humidity environment can attest).

And now for a little bit of hazmat trivia. I can hear the collective groans of emergency responders when the words “hazmat” and “trivia” are combined. In Europe, the European Union (EU) has developed six types of hazmat CPC designations, ranging from Type 1 through Type 6. The EU Standard recognizes one type of suit that is not in use here in the United States, which is the Type 2 non-encapsulating vapor-protective suit. This suit is akin to a more robust version of the EPA Level B ensemble and resembles a diving dry suit.

In terms of respiratory protection, we know that the SCBA or SAR provides the highest possible level of respiratory protection and that the SCBA is used in most circumstances due to its availability (carried on all fire apparatus). If it is determined as part of our risk-based response methodology (matching the level of protection to the level of hazard presented by the product) that it may be possible for personnel entering the Hot Zone to utilize an APR, what guidelines exist to aid us in our determination of the applicable type of respiratory protection?

Most Hazmat Technicians will state that an APR can be utilized when the product can be identified, the concentration of the product can be determined, an oxygen-deficient atmosphere does not exist, and the concentration of the product does not meet or exceed the Immediately Dangerous to Life or Health (IDLH) value. This description is only partially correct. Under most circumstances, it is true that an APR can be used at product concentrations below the IDLH value. This is not always the case, however. In the 29 CFR 1910.134 OSHA Respiratory Standard, Assigned Protection Factors (APF’s) are stipulated for varying types of respiratory protection (i.e. an APF of 50 for a full-facepiece APR). The Maximum Use Concentration is defined as the product of the APF multiplied by the OSHA Permissible Exposure Limit (PEL) of the contaminant. For example, the IDLH value for Ethylene Oxide is 800 parts per million (ppm) and the OSHA PEL is one ppm. If we are utilizing a full-facepiece APR the APF is 50, therefore the MUC equals 50 (1 ppm) equals 50 ppm. In all actuality, we are required to utilize an SCBA at concentrations exceeding 50 ppm, which is far below the 800 ppm IDLH value.

Another point of discussion for emergency responders is the compatibility of selected PPE with the products that may be encountered.

It is imperative to identify the products involved and the compatibility of the CPC ensemble with those products prior to making entry into the Hot Zone if at all possible. As Hazmat Technicians, we realize that no single ensemble will protect against all hazards. In retrospect, do we always determine PPE compatibility prior to entry? We should make every attempt to do so.

How do we determine the aforementioned compatibility? It is actually very simple.

All CPC manufacturers provide chemical compatibility data for their products. Such information can oftentimes be found on the manufacturer’s website or can be requested from the manufacturer on a CD. The most important data given to us as Hazmat Technicians is the breakthrough time for the particular PPE item for a representative array of chemicals, which is the time elapsed between the chemical contacting the item of PPE and the chemical being detected inside the item of PPE. It is also true that emergency responders oftentimes forget about the chemical compatibility of hazmat boots and gloves, as these items are essential elements of the CPC ensemble.

Speaking of CPC ensemble “accessory” items, what accessory items may be utilized as a part of the ensemble? The list varies with the level of protection utilized and the environment encountered, but may include inner and outer gloves, boots, head protection, flash protection, and/or boot covers to name a few.

A question that is frequently encountered is “Are our vapor-protective ensembles compliant with the relevant NFPA Standard?”  The relevant NFPA Standards for CPC are NFPA 1991 Standard on Vapor-Protective Ensembles for Hazardous Materials Emergencies, NFPA 1992 Standard on Liquid Splash-Protective Ensembles and Clothing for Hazardous Materials Emergencies, and NFPA 1994 Standard on Protective Ensembles for First Responders to CBRN Terrorism Incidents. NFPA 1991 states that vapor-protective CPC ensembles are required to pass rigid initial certification tests, however it is optional for such ensembles to provide the wearer with flash fire protection. Although some vapor-protective ensembles provide integral flash protection, the vast majority of flash protection is provided by an additional “flash suit” or “flash cover” worn over the vapor-protective ensemble.

During the NFPA 1991 certification process, vapor-protective ensembles are subjected to various durability tests, with many ensembles requiring the utilization of a flash suit to pass the aforementioned durability tests. The answer to the preceding question is therefore that many vapor-protective ensembles are not NFPA 1991 compliant unless accompanied by a flash suit or cover. We should definitely be cognizant of any flash or flammability hazard to avoid being “shrink-wrapped” in a dire situation. As we know, the probability of responders wearing flash protection with their vapor-protective ensemble is historically low due to the further restrictions in mobility and visibility resulting from an additional layer of CPC.

In the realm of liquid splash-protective ensembles, a point of controversy is the decision to tape or not to tape. To begin with, all hazmat personnel should realize that duct tape is not an acceptable product to be used at hazmat incident scenes for the taping of PPE. When we train with our PPE, we use duct tape due to the inexpensive cost compared with chemical protective tape (chem tape). Due to the fact that we “fight like we train,” some responders resort to the use of duct tape at actual incidents instead of using the proper product.

In the matter of “to tape or not to tape” with liquid splash-protective ensembles , many responders hold to the theory that if we need to tape the interfaces between PPE components we should wear a vapor-protective ensemble. I personally believe that such taping is practical, however only if tempered with the realization that the taping is only for additional splash protection (such as in the chin area at the interface between the SCBA mask and the suit itself) and that if any vapor hazard is presented a vapor-protective ensemble should be donned.

Expounding on the topic that we “fight like we train,” there are many training activities that we can perform to increase our suit confidence levels and gain valuable suit time while also being fun and breaking the monotony of routine training. Such activities oftentimes require minimal equipment and should be performed wearing training suits.

One training activity that can be performed is to don Level A CPC and throw a football back and forth to demonstrate the reduction in mobility for the wearer. Another possible training activity is to perform routine station cleaning activities or other manual activities in Level A CPC. I would highly recommend conducting the activities out of sight of the public to prevent civilians from becoming concerned.

Level A ensemble confidence can also be increased by constructing a diminishing clearance area in which the wearer is required to remove his or her arm from their sleeve, loosen their SCBA, and rotate it around to pass through the restricted area.

In conclusion, it is critical that hazmat personnel exhibit a thorough knowledge of the use and limitations of the various types of PPE utilized. This knowledge should be gained through recurring training in both the practical and classroom arenas and the accumulation of “suit time.” As for the question, “Is there such a thing as a ‘Level A’ hazmat suit?”, the answer is no. A Level A CPC ensemble is comprised of a vapor-protective suit and the proper respiratory protection (SCBA or SAR). The truth is that most hazmat personnel will still refer to a vapor-protective suit as a Level A suit, however, now you can amaze your fellow team members with your PPE knowledge.

I know-hazmat humor is not usually appreciated. Remember-be safe out there and visit www.nchazmat.com for information on our upcoming Hazmat Challenge in August.

Glenn Clapp is President of the North Carolina Association of Hazardous Materials Responders and is a Fire Training Commander (Special Operations) for the High Point Fire Department. He is a Technician-Level Hazmat Instructor, a Law Enforcement Hazmat Instructor, and is a Certified Hazardous Materials Manager and Certified Fire Protection Specialist.
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