In addition to the above named health hazards, hazmat technicians also face the same problems as structural firefighters when it comes to cardiac and heat related injuries, but on a higher magnitude. A firefighter involved in structural fire fighting operations that suffers a cardiac arrest at a residential dwelling only has to be evacuated to the front yard for treatment to begin. A hazmat technician that suffers a cardiac arrest while working on top of a leaking anhydrous ammonia rail car presents a different set of circumstances entirely. The hazmat technician must be lowered from the top of the rail car. This will necessitate the deployment of the Rapid Intervention Team. Then the injured technician must be transported through the hot zone and decontaminated before any medical treatment can begin. This lag time will most certainly put the patient’s treatment outside of the four to six minute window where brain death starts to occur.
Effective medical monitoring of the hazmat entry team may help to prevent this scenario from occurring.
Medical Monitoring of HazMat Entry Teams: An Overview
OSHA Standard 29 CFR 1910.120 mandates medical monitoring or surveillance for all HazMat team members. Many people may think that this is merely the act of taking a pulse and blood pressure before the entry team enters the hot zone. While this part is true, the medical monitoring of a HazMat team is actually an in-depth, four part process consisting of a baseline physical before the member joins the team, annual physicals while the member is part of the team, an exit physical when the member leaves the team and any exposure specific physicals or follow up exams that are deemed necessary. These four steps are in addition to the medical monitoring done at the incident scene.
The baseline physical includes a detailed, comprehensive health history that includes any previous chemical exposure. A complete physical examination is also administered that includes sight and hearing tests and laboratory blood work. The lab work is extensive and tests for complete blood count, kidney and liver function, blood sugar and urea nitrogen, creatinine, sodium, potassium, chloride, magnesium, calcium, inorganic phosphorous, total protein, albumin, globulin, total bilirubin, alkaline phosphatase, lactate dehydrogenase, gamma glutamyl transpeptidase, aspartate aminotransferase, alanine aminotransferase, uric acid and urine tests. These tests are used to obtain baseline numbers for future reference should the member undergo a chemical exposure. Electrocardiograms and chest x-rays are also taken.
The annual physical is a repeat of the initial baseline physical. It is used to update the medical history of the member as well as to verify the member’s fitness for duty.
The member also receives an exit physical when their tour on the HazMat team comes to an end. This is also a repeat of the initial baseline physical and serves as an endpoint in terms of monitoring the member for possible chemical exposure. It helps to determine if later medical claims are related to their service on the team.
The exposure specific physical is given whenever a member is exposed to a chemical, whether symptoms are present or not. This includes a routine physical examination and laboratory tests geared toward the specific chemical involved in the exposure.
Medical Monitoring of HazMat Entry Teams
Heat related injuries are one of the biggest concerns that HazMat teams face during entry into the hot zone. This is especially true when dealing with longer incidents or incidents where higher temperatures are involved. “Higher” temperatures can be somewhat misleading. Heat related injuries must be planned for anytime the ambient temperature reaches 70 degrees Fahrenheit or more. The Chemical Protective Clothing (CPC) that the entry team — and the teams doing decontamination activities as well — must wear induces heat stress on the member’s body. Due to the construction and material of the CPC, the body is unable to cool itself. This is due to many factors including the inability of sweat to evaporate while inside the CPC, the humid atmosphere inside the CPC, heat buildup inside the CPC, the weight of the CPC and SCBA and warm air inside the CPC that is expelled by the member through the exhalation valve on the SCBA. Medical monitoring of team members prior to entry into the hot zone may help to identify those members whom, for whatever reason, are not fit to don CPC.
The pre-entry medical monitoring conducted by many HazMat teams is usually just a cursory blood pressure and pulse check, but it needs to be much more if medical monitoring is to be used as a risk management tool for injury reduction of all types and not just heat stress.
The most comprehensive pre-entry medical monitoring is a six-step process. A complete set of vital signs including blood pressure, pulse, rate of respiration and temperature should be taken. A 10 second EKG rhythm strip should also be taken if ALS personnel are available on scene. Any rashes, open wounds or sores and sunburn should be examined. The member’s mental status should be examined to make sure that he or she is up to the task at hand. A recent medical history — covering the previous 72 hours — needs to be taken as well. The member needs to be weighed as a baseline to determine fluid loss over the course of the incident. This entire process should take approximately five minutes. Finally, the member needs to be adequately hydrated with eight ounces of water or diluted sports drink prior to entry.
The information gathered during the pre-entry medical monitoring process should not just be written down and forgotten. Medical personnel —preferably ALS — must evaluate the information to ensure that the member is physically and mentally fit to enter the hot zone. Rules for exclusion from the hot zone vary by jurisdiction, but the following are some examples:
- An irregular pulse or a pulse rate above 70 percent of the maximum heart rate (220 – age x 0.7)
- A temperature higher than 99.5 degrees Fahrenheit
- Open sores or wounds or significant sunburn — these would be an easy route for chemicals to get into the body should the integrity of the CPC be breached for any reason
- Altered mental status, blood pressure greater than 150 systolic or 100 diastolic
- Respiratory rate greater than 24 breaths per minute
- Abnormal lung sounds
- Recent onset of any medical problems — including diarrhea, dehydration and vomiting
- Any alcohol consumption within the past 24 hours.
All of the gathered medical information must be carefully analyzed before a team member makes entry into the hot zone. The adrenaline rush common in fire fighting is also present in hazmat response as well. However, large deviations in vital signs cannot be attributed to this cause. Any large deviations in the accepted norms must be used to disqualify any team member from making entry into the hot zone.
Medical monitoring of the entry while they are in the hot zone is difficult, but not impossible. The entry team should be kept in sight whenever possible so that they can be visually monitored at all times for fatigue. Radio communications should be monitored for slurred speech or inappropriate comments. These audible signals may be clues to a potential problem. Should any members of the entry team complain of chest pains, dizziness, weakness, shortness of breath or headache, the entire entry team needs to be removed to the decontamination area as soon as possible. The entire team is removed as a precautionary measure should the injured member need assistance navigating through the hot zone or the decontamination corridor.
Recent technological advances have made medical monitoring of the entry team possible in real time. Each member of the entry team wears a monitoring device that is strapped to the member’s chest under his or her shirt. The monitor sends back information in real time to a laptop computer attached to an antenna. This monitoring station could be located anywhere, but the best locations are either in the command post or on the hazmat rig with the research sector. The information sent back to the laptop includes pulse, activity level and temperature of each entry team member. This information can be downloaded and made part of the incident report and the team member’s permanent medical file for future reference.
How This Information Can Be Used
Each entry team member will have his or her own “window” on the computer with the above information displayed on it. This computer needs to be monitored constantly by EMS personnel — preferably a paramedic. If a member’s pulse becomes irregular or too rapid, that member needs to be removed from the hot zone. Increasing body temperature is a very good indicator of heat stress. If a member’s body temperature begins to increase too rapidly, that member needs to leave the hot zone as soon as possible before a heat injury can set in. A decrease in a member’s activity level can mean fatigue, dehydration or a more serious problem. Once a decreased activity level is detected, the other entry team members need to be notified so they can check on their partner. This person may need to be evacuated from the hot zone in short order. By monitoring the entry team in this fashion, a problem may be detected and measures put into place to correct it before an injury occurs.
There are two problems with this equipment however. The first is the price. It costs approximately $25,000 for a set to equip four team members with monitors. The second is staffing. For this system to be truly effective, it must be monitored constantly. This may not be possible depending on the magnitude of the incident and/or the number of personnel that are on location.
How long should an entry team stay in the hot zone? To answer this question, several other questions need to be answered. How far must the entry team walk in order to enter the hot zone? What size bottles are being utilized on the team’s SCBA? What are the weather conditions? (How hot or cold is it?) What type of work will the entry team be doing? (Aggressive spill and leak control or just a reconnaissance?) What is the physical condition of the entry team? All of these questions must be considered before an entry team is sent into the hot zone. Anything else is asking for trouble. Another component of this equation is the decontamination corridor. In structural fire fighting, when the low-pressure alarm goes off on the SCBA, the firefighter only has to make it to the front door so he can take his mask off. The hazmat technician must be thoroughly decontaminated before he can take his SCBA off. This lag time must be figured into any calculations for the length of time that the entry team may stay in the hot zone.
Medical monitoring is an ongoing process throughout the duration of the incident. The entry team must be thoroughly examined once they are decontaminated. The post-entry examination is virtually identical to the pre-entry examination. Vital signs are retaken and the members are checked to see if they have been exposed to any chemicals or if they are presenting any signs or symptoms of heat injury.
Vital signs should be reassessed every five to 10 minutes until they are within 10 percent of the original baseline vitals taken during the pre-entry examination. Any new or unusual symptoms should be reported to the HazMat officer as soon as possible as should any weight loss of three percent or more from the pre-entry body weight.
Hydration may be the most important aspect of medical monitoring. It is possible to lose up to 3,500 cc/hour (almost one gallon) of fluid while working in CPC. This loss of fluid is manifested as a change in body weight. Fluids must be readily available throughout the incident. The minimum rehydration rate is eight ounces of fluid for every half pound of body weight lost. This fluid can be water, fruit juice or a diluted sports drink (Gatorade, All Sport, etc.). Whichever fluid is chosen, it should not be ice cold, but rather chilled to approximately 40 degrees Fahrenheit. At this temperature, it is easier for the body to absorb. Caffeinated, alcoholic or carbonated beverages should not be used. Salt tablets should be avoided as well as most people get enough salt in their diet. Oral fluid intake is preferred, but intravenous (IV) support can be used as well assuming that ALS personnel are on location. It is also important to note that thirst is not a reliable indicator of the team member’s level of hydration.
Medical monitoring and hydration help to keep the entry teams healthy and also serve to evaluate the members’ fitness for continued participation in the incident. Ideally, once an entry team has completed its task in the hot zone and has been decontaminated, they should be done for the day. On large-scale incidents or on occasions where staffing is in short supply, this may not be possible. Rather than sending the same entry teams into the hot zone time after time, they should be rotated with other team members in the decontamination or research sectors. In any case, the information gathered during medical monitoring can help to establish the point where a team member must be restricted from either further entries into the hot zone or from further duties on the incident scene altogether.
Other Ways to Reduce Injuries In the Hot Zone
The way to prevent heat stress in a team member is to keep his or her body cool. This can be accomplished by utilizing ice vests, fixed line cooling units or body cooling units. These units all have their advantages and disadvantages. Depending on the design, ice vests may not make a noticeable difference in the body’s core temperature. Fixed line cooling units utilize a fixed line — as the name implies — to remove hot air from the CPC. This line may prove to be more trouble than its worth due to the tripping hazards that it presents. The body cooling suit is the most effective as it cools the entire body. It also adds weight to the member, thereby increasing fatigue and decreasing the available work time in the hot zone.
If the entry team must make another entry into the hot zone, they must be cycled through a rehabilitation sector first. This area should be located in the cold zone and it should be large enough to hold several personnel. The post-entry examination and hydration can be accomplished here. The members should be allowed to rest here, out of the elements, where they can be warmed or cooled depending on the ambient conditions. Food should be available, but the normal hot dogs and doughnuts should be avoided, as they are heavier and more difficult for the body to digest. Granola bars and broth would be better choices as they are lighter and can be more easily digested.
Crew rotation must also be considered on longer incidents. It makes no sense to work the same two entry teams to exhaustion while other trained team members are ready and available to form additional entry teams.
Properly planned and executed, medical monitoring is a proactive way to reduce injuries to hazmat entry teams. This applies not only to the monitoring at the incident, but also to the annual physicals as well. The difficulties presented by a team member going down in the hot zone make medical monitoring imperative. There is no excuse for the death of a team member due to heat stress because he or she was allowed to work in the hot zone too long and could not be decontaminated in time for medical intervention to begin.
While the focus of this paper has been on the entry teams, the decontamination teams cannot, and must not be neglected. The teams in the decontamination corridor also wear CPC and will be in the gear just as long, if not longer, than the entry team. They face the same hazards of heat stress injuries and should be monitored and rotated out in the same manner as the entry teams.
Luckily, hazardous materials responders have not lost a member while working on a hazmat incident. This is due in part to the fact that hazmat responders know the hazards of the chemicals that they deal with and don’t often suffer from the tunnel vision that structural firefighters have when it comes to “putting the wet stuff on the red stuff.” The other component is of course, comprehensive medical monitoring. With training, improvements to current medical monitoring policies and procedures and a little old fashioned luck, we will be able to maintain this perfect record.