Principles of Decontamination

Objectives Define contamination and decontamination Differentiate between the concepts of exposure and contamination Identify the different types of contaminants and routes of contamination

Objectives Identify the physical and chemical methods of decontamination Describe the Hazard Control Zones Identify three levels of PPE and Special Equipment for decontamination List health care considerations for handling a contaminated patient

Case Presentation January 6, 2005 Let’s start with a current case-this past January, this train wreck occurred in a relatively rural area of South Carolina

Case Presentation 8 people die, many more exposed when a train carrying chlorine crashed, rupturing one of its tankers and releasing the toxic gas into the air. There were at least three hazardous chemicals on the train but officials were most concerned about the chlorine gas, which affects respiratory and central nervous systems. It can damage the throat, nose, eyes and can cause death.

Case Presentation Decontamination sites set up at nearby schools. Officials did not know how many people had been decontaminated at USC-Aiken and Midland Valley High School. At the university, two tents were set up. In one tent, people exposed to the chemicals removed their clothes and were washed down.

Case Presentation This is one of the agents in charge of decontamination at the site of the accident. Unless your careers take a major shift- you will most likely never be one of these workers. There is a tremendous amount of training that goes into the decontamination at a site.

Case Presentation They then moved to a second tent where they were given medical attention. Some were sent to the hospital. The process involved giving people fluid and oxygen to clear airways and showers to remove chemical residue.

Case Presentation This worked well. You can see that not all mass causality situations are attacks-many accidents. The entire process went well-the decontamination sites were established, many people were treated and then dispatched to the nearby hospitals. So why do you need to know this? These patients were all treated at the scene and dispatched. Let’s look at different scenario…

A Different Scenario March 19, 1995, in a crowded Tokyo subway station, religious fanatics set off a Sarin gas bomb. Hundreds of people were exposed, covered with the residue and breathing in this toxic gas Monday morning rush hour in Tokyo disintegrated into chaos as toxic fumes were released into the subway station. Quickly escalated into a mass casualty situation. At least 565 people had to be hospitalized and several died. The exact nature of th4e chemical remained a mystery for several hours following the attack.

A Different Scenario 80% of the exposed victims ran to the nearest ED 100/472 healthcare workers showed signs of exposure and had to be treated-one was hospitalized At a chaotic scene, with many scared people, the situation is much different. Think about it- what would you do? Would you wait until the decon team is deployed, sets up and takes care of anyone more serious than you? I don’t think so. You, like everyone else, would get yourself to the nearest place of treatment if you can…and that is what happens in reality.

A Different Scenario Most do not wait This is why you need to know the basics, because you could be one of those healthcare workers! Generally with Sarin gas medical personnel must wash the victims with soap and water-hopefully at the scene. The water used to wash these patients needs to be carefully and properly disposed of in drums or containers. If you are working when a situation occurs, you need to know that you are not going to get nice, clean, decontaminated patients-you probably won’t even know what the agent is right away.

Contamination Contamination is any form of hazardous material that physically remains on people, animals, or objects. Forms of contaminants include: solids liquids gases Point out objects because the tendency is to think skin, not clothes in most cases

Exposure Exposure means that a person has been subjected to a toxic or harmful physical agent through any route of entry into the body Several routes of entry into the body: Skin absorption Ingestion Inhalation Injection Open wound contact .

Exposure vs. Contamination a person who has been contaminated has not necessarily been exposed. The term exposure is used to distinguish between simple contact and a contact with the potential of causing harm or sickness. The presence of a contaminant on the skin, for example, would not qualify as an exposure if the substance can only enter the body through ingestion. The person would be exposed when they inhale the agent-they are contaminated, like the Sarin gas, if it lies on their skin.

Contamination Routes Direct Contamination occurs through direct contact with the contaminant. Cross Contamination occurs when an uncontaminated (“clean”) person or thing comes into direct contact with a contaminated (“dirty”) person, animal or object. Direct Contamination can occur if a person has direct involvement in the release event (i.e. spill, explosion, etc.) Rushes in to render aid without proper protective gear ( a strong tendency for healthcare workers) Poor site management practices Incompatible personal protection equipment (PPE) Failure to identify potential safety problems ✔ Failure to decontaminate ✔ Lack of sufficient breathing air in any exposed area, forcing a premature removal of self-contained breathing apparatus Cross Contamination is more likely and can occur when: A healthcare worker that is cross-contaminated by coming into physical contact with contaminated patient A bystander or first responder who improperly enters the decontamination area and comes into contact with an object that has not yet been properly decontaminated

Contamination Routes Surface Permeation Surface Contaminants exist on the outer surface of a material and have not been absorbed into the material. These are typically easy to detect and remove. Common examples include dry solids such as dusts or powders. Permeation Contaminants are absorbed into a material at the molecular level. These can be extremely difficult to detect and remove and can occur with any porous material.

Contamination Routes Permeation toxicity is determined by: Contact Time Concentration Temperature Physical State Contact Time: longer the time of contact, greater probability and ultimate extent of permeation Concentration: greater concentration of contaminant, greater potential Temperature: increased temperature increases rate of permeation Physical State: gases, vapors, and low viscosity liquids tend to permeate more readily than high viscosity liquids and solids

Decontamination Hydrochloric Acid is a perfect example-the more contact time, the greater the concentration, the more surface area covered the greater extent of the damage.

Decontamination Decontamination is the process of reducing and preventing the spread of contaminants from a hazardous materials scene. Emergency decontamination is called for when exposures can cause severe, imminent or long-term harm unless removed immediately. Emergency Decontamination situations include: Victims splashed with concentrated acids or caustics Victims splashed with pesticides or other skin-absorbed toxins Pregnant victims exposed to chemicals which may induce dangerous or teratogenic effects to the fetus

Decontamination Showers are set up at the scene of decontamination sites so that any agent that can be physically removed or reduced can happen safely and effectively

Physical Decontamination Physical decontamination involves physically removing contaminant from the contaminated person or object. Physical Decontamination Techniques Include: ✔ Dilution ✔ Brushing or Scraping ✔ Absorption

Chemical Decontamination The process of removing or reducing the threat from a specific contaminant by rendering it less harmful through a chemical change Chemical Decontamination Techniques Include: Chemical Degradation – application of a degradation agent to alter the chemical structure of hazardous material Note: Degrading agents should never be applied directly to skin! (examples: bleach, drain cleaner, washing soda, lime, detergent, isopropyl alcohol) Neutralization – application of either an acid or caustic to a corrosive liquid spill to bring the pH of the spill towards neutral (pH=7) Solidification – application of a material which chemically bonds the contaminant to another object or encapsulates it Disinfection – application of materials which will inactivate or kill pathogenic microorganisms (Note: you can never assume that field disinfection will be 100% effective in killing all traces of an organism) Sterilization – destroys all microorganisms in or on an object (examples: steam, concentrated chemical agents, ultraviolet light radiation)

Hazard Control Zones The terms Hot and Cold have no relevance to temperature. Cold Zone indicates the absence of contaminants. Hot Zone indicates an area immediately containing, or within the effect of, an uncontained hazardous material (depicted as a simple red circle surrounding the hypothetical spill below). In order to protect people from getting into the Hot Zone as well as minimize the migration of hazardous material outside of the Hot Zone, a Warm Zone is designated as a barrier to traffic. The best analogy is digging a moat around the Hot Zone (depicted in orange below). Our moat has a single “drawbridge” which is the sole avenue for moving into or out of the Hot Zone. This is known as the Decontamination Corridor – a clearly marked pathway through the Warm Zone which can be tightly controlled to prevent the spread of contaminants. All decontamination takes place within the Decon Corridor. The drawbridge metaphor is extremely accurate as the Decon Corridor may be “opened” or “closed” to traffic at the direction of a Safety Officer managing the decontamination process. The near end of the Decon Corridor (which opens into the Cold Zone) is often referred to as the “clean end” of the corridor, while the opposite end is known as the “dirty end.” People and equipment passing outbound through the corridor will be subjected to the appropriate decontamination processes to insure that they are “clean” or free from contaminant before they exit the Clean End.

PPE PPE falls into three categories, Level A through Level C, in descending order of protection. Level C PPE (splash suits, gloves, boots, organic vapor and HEPA combination canister air-purifying respirators) should be available for health care

Special Equipment Positive and Negative Pressure Rooms Fixed Ventilation Systems Safety Showers Eyewash Stations Various pieces of special equipment can greatly assist the process of decontamination. Some may be mobile and erected as needed, while others may be permanent in fixtures where hazardous materials are frequently stored and handled. Positive and Negative Pressure Rooms – positive air pressure outside and negative pressure inside to prevent contaminants from spreading beyond containment room Fixed Ventilation Systems – primarily found in research or manufacturing facilities engaged in the use of hazardous materials Safety Showers – deluge heads deliver water at 30-50 gallons/minute. In the image at right, pulling the triangular handle will immediately trigger a cascade from the shower head above. Eyewash Fountains – often combined with emergency showers, these devices are designed to deliver a continual low-pressure stream of water to flush out the eyes. In the image at right, the flat-topped green dome covers the eyewash cups.

Health Care Considerations Patient should be fully decontaminated prior to transportation to a medical facility Receiving medical staff should be notified when handling a contaminated patient Patient should be wrapped in disposable fabric bags to prevent spread of any remaining contaminants Fatalities should be handled with same decon procedures

Health Care Considerations Health care facility-based decontamination is markedly different from field operations Health care workers are faced with medical emergencies in potentially contaminated patients Ambulatory patients are unlikely to wait for hazardous materials teams for transport Because potential exposures result from proximity to or contact with a contaminated patient rather than direct contact with contaminants

Health Care Considerations OSHA has specified that health care facility personnel decontaminating patients must be trained to operations level 8 hours or to a demonstrated competency level

Decontamination Questions Pause for discussion before proceeding to the following 5 multiple choice questions.

Question #1 Forms of contaminants include: Liquids Direct Injection Surface The correct answer is “a. Liquids.”

Question #2 The presence of a contaminant on the skin always qualifies as an exposure True False The correct answer is “b. False.”

Question #3 Decontamination starts in the Hot Zone True False The correct answer is “b. false.” All decontamination takes place within the Decon Corridor.

Question #4 Special Equipment includes all the following except: Positive Pressure Rooms Stethoscopes Safety Showers Eyewash Stations The correct answer is “b. Stethoscopes.”

Question #5 Health care considerations for contamination events include: Fatalities do not require decontamination Ambulatory patients will always be transported to the ED via ambulance Both Neither The correct answer is “D. Neither.”

This completes the current presentation. End presentation and distribute activity survey.