Protection Versus Productivity
Vol 20 No 4
When one begins to consider emergency response in general and with regard to Hazardous Materials in particular, it is only prudent to give some thought to the protection of the responder from the hazards present. How much and what kinds of protection are required? There is not always an easy answer to this question; sometimes we just do not know what we are dealing with and the first reconnaissance into the site of the incident may be for the purpose of answering that very question.
The prudent response to a situation of this type is, of course, "Level A all the way"; at least until we know what we are up against. Even then we may not be absolutely safe. "Level A" protection as we commonly think of it in connection with Hazardous Materials incidents does not, for example, afford adequate protection against an explosion or the collapse of a supporting structure.
The only way that one could achieve anything like complete protection would be to enclose the operator in a three-inch-thick steel container with a bolted-on cover and provision for supplying a breathable atmosphere. This would obviously afford maximum protection and is close to what is actually used in the case of deep sea diving. The problem is that while the worker is protected to something approaching the maximum possible degree, his ability to perform work rapidly approaches zero.
This is the trade-off that must be made in any instance where protective equipment is mandated and utilized. In many inner city neighborhoods house holders feel compelled to install bars over their windows to protect their homes from intrusion. These are effective but people have died because the fire department personnel could not get through the bars in time to accomplish a rescue. The rubber gloves that are used by medical personnel when in contact with a patient or specimens from a patient will protect against infection but they also reduce tactile sensitivity which is so vital in the performance of certain very delicate tasks.
Seat belts in automobiles save lives; no question about that. But, there have been cases in which people have died because they could not free themselves from a jammed buckle.
Helmets for those who ride motorcycles unquestionably vastly reduce the number of head injuries but they also restrict the vision and hearing of the motorcycle rider and thus enhance the chance of an accident.
The same compromise must be reckoned with in regard to protective gear utilized by emergency responders and measures must be taken to deal with the "down side" component of the equation. Goggles and shields protect the eyes from foreign objects but at the same time they may interfere with peripheral vision or the use of prescription glasses. Self contained breathing apparatus (SCBA) allows a worker to have uncontaminated breathing air in a hostile environment but this safety is achieved at the cost of increased weight that must be carried on the wearer's back and very stringent limits on the time that he can remain within the contaminated area.
Encapsulating suits do just what their name says, they encapsulate and isolate the wearer from the environment. This is, of course a good and necessary thing if you are talking about an atmosphere contaminated with a toxic substance such as, chlorine or hydrogen cyanide but it is a very bad thing if you are talking about the thermal stress imposed on the wearer of one of these suits when he is trying to work in an environment where the ambient temperature is 105 degrees F.
SCBA, while making existence in encapsulated suits possible, does also have a down side. It adds weight and those that are closed loop systems i.e. "re-breathers" create additional heat load due to the exothermic reaction taking place in the scrubbers which are required to remove excess CO2 from the breathing mixture.
Air conditioning engineers use a factor of approximately 300 BTU /hr/ body when calculating the thermal load of an area such as a school or auditorium to determine the amount of air conditioning to install. A responder doing heavy work in the hot sun of a southwestern summer would produce every bit of that heat if not a great deal more. This is just the heat produced by the body within the suit. Additional heat will be generated by the sun beating down on the suit and its wearer and possibly other equipment such as closed-loop SCBA. Even on a moderately warm day the temperature inside one of these garments can reach well into the triple digit range. When this happens the wearer begins to feel like he is being boiled in his own juices like an Easter ham; and to some extent he is.
When the temperature rises above that of the normal body, cooling becomes necessary. This is normally accomplished in humans and other mammals by means of the excretion of fluid or "sweating". The evaporation of this fluid cools the body. In an area such as the Texas Gulf coast, the high humidity retards evaporation and sweating is very noticeable; thirty minutes of hard work in the noonday sun will leave one "wringing wet". In the desert southwest sweating is much more efficient as a means of cooling the body and the fluid evaporates almost as soon as it is excreted. This causes the erroneous impression that "you don't sweat in the desert". You do, but it is gone so quickly that you don't ever see it. In either case the body loses a tremendous amount of fluid, which contains vital electrolytes. If this fluid, and its contained electrolytes, is not replaced immediately dehydration, heat stress and ultimately heat stroke which can be fatal will follow. The amount of fluid that a body can lose while in an encapsulated suit is amazing. It is not uncommon to have responders coming in to have their air bottles replaced standing, literally, knee-deep in their own sweat.
Now, this is not to condemn encapsulating suits, far from it. Under certain conditions these garments provide the only relatively safe means of egress; but, as with all other forms of protective equipment, safety is achieved at a price and we must be prepared to pay that price without harm to our personnel.
For this reason medical surveillance and personnel monitoring is an absolute necessity when workers are using encapsulating suits. It should, of course, be a part of every response activity but especially in instances where encapsulating suits are worn. If the situation is so hazardous as to require encapsulating suits it is dangerous enough to require full blown medical support.
Each time a worker comes in for an air bottle exchange, the encapsulated suit should be opened to allow ventilation of the interior. At the same time medical personnel should monitor the vital signs of the worker and no one should be permitted to return to the work site until these are within normal limits. Body temperature, pulse rate and blood pressure must be stable and within normal limits. The first order of business should be the replacement of fluids and electrolytes. It is not uncommon for a worker emerging from an encapsulated suit to drink two liters of fluid at once. No one exhibiting signs of heat stress should be allowed to return to the work site until these have been completely abated. Personnel in encapsulated suits must be cooled of as soon as possible. This can often be achieved by means of a fan, a smoke ejector works well, or, better yet, an evaporative cooling system. Ice packs are also effective. Of course the best of all possible worlds is a recovery trailer equipped with refrigerated air conditioning. However, regardless of how it is accomplished, it is imperative that core temperatures be reduced to normal levels as soon as possible.
Other protective equipment also provides protection at a price. Footwear designed to protect the wearer from mechanical injuries such as cuts, crushes or punctures from debris or chemical exposure from runoff or spilled material are necessities but they do cause the wearer to be clumsy and less sure footed than normal.
Gloves are required to protect against mechanical injury as well as chemical exposure. It is not uncommon for a responder to wear three or more different types of gloves one over the other while attempting to perform meaningful work. While conditions may certainly warrant these hand covers manual dexterity rapidly approaches zero. During the course of a drill or simulation where workers are equipped with gloves suitable for work on or near the hazardous material which is the subject of the exercise, ask them to attempt to write their name on a 3X5 card with an ordinary pen or pencil. You will very likely be surprised at the difficulty of the task.
Specialized equipment, such as flak vests or radiation shielding, which are unique to a particular type of response, impose additional weight on the wearer. The weight of these items further reduces the capacity of an individual to perform meaningful work in an emergency situation.
Finally, protective equipment is heavy and its weight imposes stress on the wearer. No one piece of equipment can be said to be the culprit but collectively they produce a significant amount of weight that the operator must carry before he even picks up a tool. Go down the list of protective equipment that a responder would be expected to wear or carry during a typical response; pile all of the items on a bathroom scale and note the total weight. This is the price of protection.