DecontaminationIntroductionDecontamination - the process of removing or neutralizing contaminants that have accumulated on personnel and equipment - is critical to health and safety at hazardous waste sites. Decontamination protects workers from hazardous substances that may contaminate and eventually permeate the protective clothing, respiratory equipment, tools, vehicles, and other equipment used on site; it protects all site personnel by minimizing the transfer of harmful materials into clean areas; it helps prevent mixing of incompatible chemicals; and it protects the community by preventing uncontrolled transportation of contaminants from the site. Show
This chapter describes the types of contamination that workers may encounter at a waste site, the factors that influence the extent of contamination, and methods for preventing or reducing contamination. In addition, this chapter provides general guidelines for designing and selecting decontamination procedures at a site, and it presents a decision aid for evaluating the health and safety aspects of decontamination methods. The chapter does not cover decontamination of radioactively contaminated personnel or equipment. A health physicist should be consulted if this situation arises. Decontamination PlanA decontamination plan should be developed (as part of the Site Safety Plan) and set up before any personnel or equipment may enter areas where the potential for exposure to hazardous substances exists. The decontamination plan should:
The plan should be revised whenever the type of personal protective clothing or equipment changes, the site conditions change, or the site hazards are reassessed based on new information. Prevention of ContaminationThe first step in decontamination is to establish Standard Operating Procedures that minimize contact with waste and thus the potential for contamination. For example:
In addition, Standard Operating Procedures should be established that maximize worker protection. For example, proper procedures for dressing prior to entering the Exclusion Zone will minimize the potential for contaminants to bypass the protective clothing and escape decontamination. In general, all fasteners should be used (i.e., zippers fully closed, all buttons used, all snaps closed, etc.) Gloves and boots should be tucked under the sleeves and legs of outer clothing, and hoods (if not attached) should be worn outside the collar. Another pair of tough outer gloves is often worn over the sleeves. All junctures should be taped to prevent contaminants from funning inside the gloves, boots, and jackets (or suits, if one-piece construction). Prior to each use, the personal protective equipment (PPE) should be checked to ensure that is contains no cuts or punctures that could expose workers to wastes. Similarly, any injuries to the skin surface, such as cuts and scratches, may enhance the potential for chemicals or infectious agents that directly contact the worker's skin to penetrate into the body. Particular care should be taken to protect these areas. Workers with large areas of damaged skin should be kept from working on site until the skin heals. All personnel should be trained in the Standard Operating Procedures for minimizing contact and maximizing worker protection, and these procedures should be enforced throughout site operations. Types of ContaminationContaminants can be located either on the surface of personal protective equipment or permeated into the PPE material. Surface contaminants may be easy to detect and remove; however, contaminants that have permeated a material are difficult or impossible to detect and remove. If contaminants that have permeated a material are not removed by decontamination, they may continue to permeate to either surface of the material where they can cause an unexpected exposure. Five major factors affect the extent of permeation:
Decontamination MethodsAll personnel, clothing, equipment, and samples leaving the contaminated area of a site (generally referred to as the Exclusion Zone) must be decontaminated to remove any harmful chemicals or infectious organisms that may have adhered to them. Decontamination methods either (1) physically remove contaminants, (2) inactivate contaminants by chemical detoxification or disinfection/sterilization, or (3) remove contaminants by a combination of both physical and chemical means. Various decontamination methods are listed in Table 1. Physical Removal In many cases, gross contamination can be removed by physical means involving dislodging/displacement, rinsing, wiping off, and evaporation. Physical methods involving high pressure and/or heat should be used only as necessary and with caution since they can spread contamination and cause burns. Contaminants that can be removed by physical means can be categorized as follows:
Table 1. Some Decontamination MethodsREMOVAL
INACTIVATION
Chemical RemovalPhysical removal of gross contamination should be followed by a wash/rinse process using cleaning solutions. These cleaning solutions normally utilize one or more of the following methods:
Table 2. General Guide to Solubility of Contaminants In Four Solvent Types
*WARNING: Some organic solvents can permeate and/or degrade the protective clothing.
Many factors, such as cost, availability, and ease of implementation, influence the selection of a decontamination method. From a health and safety standpoint, two key questions must be addressed:
Testing for the Effectiveness of DecontaminationDecontamination methods vary in their effectiveness for removing different substances. The effectiveness of any decontamination method should be assessed at the beginning of a program and periodically throughout the lifetime of the program. If contaminated materials are not being removed or are penetrating protective clothing, the decontamination program must be revised. The following methods may be useful in assessing the effectiveness of decontamination. Visual Observation There is no reliable test to immediately determine how effective decontamination is. In some cases, effectiveness can be estimated by visual observation.
Wipe Sampling Wipe testing provides after-the-fact information on the effectiveness of decontamination. In this procedure, a dry or wet cloth, glass fiber filter paper, or swab is wiped over the surface of the potentially contaminated object and then analyzed in a laboratory. Both the inner and outer surfaces of protective clothing should be tested. Skin may also be tested using wipe samples. Cleaning Solution Analysis Another way to test the effectiveness of decontamination procedures is to analyze for contaminants left in the cleaning solutions. Elevated levels of contaminants in the final rinse solution may suggest that additional cleaning and rinsing are needed. Testing for Permeation Testing for the presence of permeated chemical contaminants requires that pieces of the protective garments be sent to a laboratory for analysis. Health and Safety HazardsWhile decontamination is performed to protect health and safety, it can pose hazards under certain circumstances. Decontamination methods may:
The chemical and physical compatibility of the decontamination solutions or other decontamination materials must be determined before they are used. Any decontamination method that permeates, degrades, damages, or otherwise impairs the safe functioning of the PPE is incompatible with such PPE and should not be used. If a decontamination method does pose a direct health hazard, measures must be taken to protect both decontamination personnel and the workers being decontaminated. Decontamination Facility Design At a hazardous waste site, decontamination facilities should be located in the Contamination Reduction Zone (CRZ), i.e., the area between the Exclusion Zone (the contaminated area) and the Support Zone (the clean area) as shown in 3. The level and types of decontamination procedures required depend on several sitespecific factors including:
Decontamination procedures must provide an organized process by which levels of contamination are reduced. The decontamination process should consist of a series of procedures performed in a specific sequence. For example, outer, more heavily contaminated items (e.g., outer boots and gloves) should be decontaminated and removed first, followed by decontamination and removal of inner, less contaminated items (e.g., jackets and pants). Each procedure should be performed at a separate station in order to prevent cross contamination. The sequence of stations is called the decontamination line. Stations should be separated physically to prevent cross contamination and should be arranged in order of decreasing contamination, preferably in a straight line. Separate flow patterns and stations should be provided to isolate workers from different contamination zones containing incompatible wastes. Entry and exit points should be conspicuously marked, and the entry to the Contamination Reduction Zone (CRZ) from the Exclusion Zone should be separate from the entry to the Exclusion Zone from the CRZ. Dressing stations for entry to the CRZ should be separate from redressing areas for exit from the CRZ. Personnel who wish to enter clean areas of the decontamination facility, such as locker rooms, should be completely decontaminated. Examples of decontamination lines and procedures for personnel wearing various levels of protection are provided in an appendix to this section. Disposal Methods All equipment used for decontamination must be decontaminated and/or disposed of properly. Buckets, brushes, clothing, tools, and other contaminated equipment should be collected, placed in containers, and labeled. Also, all spent solutions and wash water should be collected and disposed of properly. Clothing that is not completely decontaminated should be placed in plastic bags, pending further decontamination and/or disposal. Table 3. Some Recommended Equipment for Decontamination of Personnel and Personal Protective Clothing and Equipment
Personal Protection Decontamination workers who initially come in contact with personnel and equipment leaving the Exclusion Zone will require more protection from contaminants than decontamination workers who are assigned to the last station in the decontamination line. In some c-ases, decontamination personnel should wear the same levels of PPE as workers in the Exclusion Zone. In other cases, decontamination personnel may be sufficiently protected by wearing one level lower protection (e.g., wearing Level C protection while decontaminating workers who are wearing Level B). The level of protection required will vary with the type of decontamination equipment used. For example, workers using a steam jet may need a different type of respiratory protection than other decontamination personnel because of the high moisture levels produced by steam jets. In some situations, the cleaning solutions used and wastes removed during decontamination may generate harmful vapors. Appropriate equipment and clothing for protecting decontamination personnel should be selected by a qualified health and safety expert. Table 4. Some Recommended Equipment for Heavy Equipment and Vehicle Decontamination
An decontamination workers are in a contaminated area and must themselves be decontaminated before entering the clean Support Zone. The extent of their decontamination should be determined by the types of contaminants they may have contacted and the type of work they performed. Emergency Decontamination In addition to routine decontamination procedures, emergency decontamination procedures must be established. In an emergency, the primary concern is to prevent the loss of life or severe injury to site personnel. If immediate medical treatment is required to save a life, decontamination should be delayed until the victim is stabilized. If decontamination can be performed without interfering with essential life-saving techniques or first aid, or if a worker has been contaminated with an extremely toxic or corrosive material that could cause severe injury or loss of life, decontamination must be performed immediately. If an emergency due to a heat-related illness develops, protective clothing should be removed from the victim as soon as possible to reduce the heat stress. During an emergency, provisions must also be made for protecting medical personnel and disposing of contaminated clothing and equipment. Decision Aid for Evaluating Health and Safety Aspects of Decontamination Methods.TEXT VERSION (Initial box on right side). Is the method effective for removing contaminants? If No, (Arrow to box on left side below) Take additional measures to prevent contamination or find another decontamination method. Consult specialists if necessary. (End) If Yes, (Arrow to second box below) Are the decontamination materials compatible with the hazardous substances present? If No, (Arrow to box on left side below) Take additional measures to prevent contamination or find another decontamination method. Consult specialists if necessary.(End) If Yes, (Arrow to third box below) Are the decontamination materials compatible with the materials to be decontaminated? If No, (Arrow to box on left side below) Take additional measures to prevent contamination or find another decontamination method. Consult specialists if necessary. (End) If Yes, (Arrow to fourth box below) Can appropriate decontamination materials or process pose health or safety hazards? If No, (Arrow to sixth box below) Method OK to use.(End) If Yes, (Arrow to fifth box below) Can appropriate protective measures be institution If No, (Arrow to box on left side below) Take additional measures to prevent contamination or find another decontamination method. Consult specialists if necessary. If Yes, (Arrow to sixth box on right side) Method OK to use.(End) Decision Aid for Emergency DecontaminationTEXT VERSION (Initial box on left side) Accident/Injury Event (Arrow to first decision diamond) Life-Saving Procedures Required? If No, (Arrow to box below) Decontaminate as much as possible (Continue to decision diamond below) Further Medical Attention or Surveillance Required? If No, (Arrow to box to the right) Report to Superiors for Instructions. (End) If Yes, (Arrow to box below) Transport to Medical Facility (End) If Yes, (Arrow to second decision diamond to the right) Contaminants Extremely Hazardous? If No, (Arrow to box on right side) Perform Life-Saving Procedures (Continue to decision arrow below) Additional Emergency Care Required? If No, (Arrow to box on left) Decontaminate as Much as Possible (Continue to decision arrow below) Further Medical Attention or Surveillance Required? If No, (Arrow to box to the right) Report to Superiors for Instructions. (End) If Yes, (Arrow to box below) Transport to Medical Facility (End) If Yes, (Continue to box below) Grossly Decontaminate and/or Cover or Wrap Contaminated Areas (End) Appendix A.Sample Decontamination Procedures for Three Typical Levels of Protectiona F.S.O.P. No. 7 Process: DECONTAMINATION PROCEDURES INTRODUCTION 1.1 The objective of these procedures is to minimize the risk of exposure to hazardous substances. These procedures were derived from the U.S. Environmental Protection Agency, Office of Emergency and Remedial Response's (OERR), "Interim Standard Operating Safety Guides (revised Sep. 82)". This version of the guides is in a format that is more appropriate for use in the field. 1.2 Protective equipment must be worn by personnel when response activities involve known or suspected hazardous substances. The procedures for decontaminating personnel upon leaving the contaminated area are addressed for each of the EPA, OERR designated levels of protection. The procedures given are for the maximum and minimum amount of decontamination used for each level of protection. 1.3 The maximum decontamination procedures for all levels of protection consist of specific activities at nineteen stations. Each station emphasizes-an important aspect of decontamination. When establishing a decontamination line, each aspect should be incorporated separately or combined with other aspects into a procedure with fewer steps (such as the Minimum Decontamination Procedures). 1.4 Decontamination lines are site specific since they are dependent upon the types of contamination and the type of work activities on site. A cooling station is sometimes necessary within the decontamination line during hot weather. It is usually a location in a shaded area in which the wind can help to cool personnel. In addition, site conditions may permit the use of cooling devices such as cool water hose, ice packs, cool towels, etc. When the decontamination line is no longer required, contaminated wash and rinse solutions and contaminated articles must be contained and disposed of as hazardous wastes in compliance with state and federal regulations. F.S.O.P. No. 7 PROCESS DECON PROCEDURES MAXIMUM DECONTAMINATION LAYOUT LEVEL A PROTECTION Maximum Decontamination Layout - Level A ProtectionTEXT VERSION EXCLUSION ZONE (Each station has a numbered hexagon and arrow pointing to next station in a line above the HOTLINE) A flow chart from Station 1: Segregated Equipment Drop, to Station 2: Boot Cover & Glove Wash, to Station 3: Boot Cover & Glove Rinse, to Station 4: Tape Removal, to Station 5: Boot Cover Removal, to Station 6: Outer Glove Removal (The arrow at Station 6 points downward across the HOTLINE into the CONTAMINATION REDUCTION ZONE. A series of numbered hexagons point downward toward the CONTAMINATION CONTROL LINE.) Station 7: Suit/Safety Boot Wash (within the CONTAMINATION REDUCTION ZONE), to Station 8: Suit/Safety Boot Rinse. The Station 8 numbered hexagon has two arrows, the first arrow points to Station 9: Change and Redress - Boot Cover/Outer Gloves, which has an upward arrow that crosses the HOTLINE reentering the EXCLUSION ZONE, and the second arrow, continuing downward to Station 10: Safety Boot Removal, to Station 11: Fully Encapsulating Suit with Hard Hat Removal, to Station 12: SCBA Backpack Removal, to Station 13: Inner Glove Wash, to Station 14: Inner Glove Rinse, to Station 15: Face Piece Removal, to Station 16: Inner Glove Removal, to Station 17: Inner Clothing Removal which has an arrow crossing downward past the CONTAMINATION CONTROL LINE, to Station 18: Field Wash (within the SUPPORT ZONE), which has an arrow across to Station 19: Redress, the final station. F.S.O.P. No. 7 PROCESS DECON PROCEDURES MAXIMUM DECONTAMINATION LAYOUT LEVEL B PROTECTION Maximum Decontamination Layout - Level B ProtectionTEXT VERSION EXCLUSION ZONE (Each station has a numbered hexagon and arrow pointing to next station in a line above the HOTLINE) A flow chart from Station 1: Segregated Equipment Drop, to Station 2: Boot Cover & Glove Wash, to Station 3: Boot Cover & Glove Rinse, to Station 4: Tape Removal, to Station 5: Boot Cover Removal, to Station 6: Outer Glove Removal (The arrow at Station 6 points downward across the HOTLINE into the CONTAMINATION REDUCTION ZONE. A series of numbered hexagons point downward toward the CONTAMINATION CONTROL LINE.) Station 7: Suit/Safety Boot Wash (within the CONTAMINATION REDUCTION ZONE), to Station 8: Suit/SCBA/Boot/Glove Rinse. The Station 8 numbered hexagon has two arrows, the first arrow points to Station 9: Tank Change and Redress - Boot Cover/Outer Gloves, which has an upward arrow that crosses the HOTLINE reentering the EXCLUSION ZONE, and the second arrow, continuing downward to Station 10: Safety Boot Removal, to Station 11: SCBA Backpack Removal, to Station 12: Splash Suit Removal, to Station 13: Inner Glove Wash, to Station 14: Inner Glove Rinse, to Station 15: Face Piece Removal, to Station 16: Inner Glove Removal, to Station 17: Inner Clothing Removal which has an arrow crossing downward past the CONTAMINATION CONTROL LINE, to Station 18: Field Wash (within the SUPPORT ZONE), which has an arrow across to Station 19: Redress, the final station. F.S.O.P. No. 7 PROCESS DECON PROCEDURES MAXIMUM DECONTAMINATION LAYOUT LEVEL C PROTECTION Maximum Decontamination Layout - Level C ProtectionTEXT VERSION EXCLUSION ZONE (Each station has a numbered hexagon and arrow pointing to next station in a line above the HOTLINE) A flow chart from Station 1: Segregated Equipment Drop, to Station 2: Boot Cover & Glove Wash, to Station 3: Boot Cover & Glove Rinse, to Station 4: Tape Removal, to Station 5: Boot Cover Removal, to Station 6: Outer Glove Removal (The arrow at Station 6 points downward across the HOTLINE into the CONTAMINATION REDUCTION ZONE. A series of numbered hexagons point downward toward the CONTAMINATION CONTROL LINE.) Station 7: Suit/Safety Boot Wash (within the CONTAMINATION REDUCTION ZONE), to Station 8: Suit/SCBA/Boot/Glove Rinse. The Station 8 numbered hexagon has two arrows, the first arrow points to Station 9: Tank Change and Redress - Boot Cover/Outer Gloves, which has an upward arrow that crosses the HOTLINE reentering the EXCLUSION ZONE, and the second arrow, continuing downward to Station 10: Safety Boot Removal, to Station 11: Splash Suit Removal, to to Station 12: Inner Glove Wash, to Station 13: Inner Glove Rinse, to Station 14: Face Piece Removal, to Station 15: Inner Glove Removal, to Station 16: Inner Clothing Removal which has an arrow crossing downward past the CONTAMINATION CONTROL LINE, to Station 17: Field Wash (within the SUPPORT ZONE), which has an arrow across to Station 18: Redress, the final station. F.S.O.P. No. 7 PROCESS DECON PROCEDURES MINIMUM DECONTAMINATION LAYOUT LEVEL A & B PROTECTION Minimum Decontamination Layout - Level A & B ProtectionTEXT VERSION (A series of three arrows in the upper right, one arrow 20 degrees above and the other arrow 20 degrees below the central arrow, indicate wind direction toward the HOTLINE.) The Equipment Drop Area (from left to right) is indicated by a rectangle with a circle below indicating the location of the Plastic sheet and a right pointing arrow to another rectangle divided by a diagonal line into the Decon Outer Garments area and the Remove Boot Covers and Outer Gloves area with a circle below indicating the location of a 10 gallon can. A dashed line cutting vertically through this rectangle indicates the HOTLINE. To the right of the HOTLINE, above the rectangle, two circles indicate the location of the Decon Solution and Water. Two arrows continue from the second divided Decon rectangle to a circle marked with an X that has an upward pointing arrow, that turns back toward the dashed HOTLINE to an area labelled Redress: Boot Covers and Outer Gloves, and crosses the dashed HOTLINE. Another arrow from the circle marked with an X continues to a rectangle indicating the area to Remove Boots/Gloves and Outer Garments (For Disposal and Off Site Decontamination) with a circle below indicating the location of a 32 gallon can. Another series of arrows pointing downward go to another rectangle, the Remove SCBA final decon area. F.S.O.P. No. 7 PROCESS DECON PROCEDURES MINIMUM DECONTAMINATION LAYOUT LEVEL C PROTECTION Minimum Decontamination Layout - Level C ProtectionTEXT VERSION (A series of three arrows in the upper right, one arrow 20 degrees above and the other arrow 20 degrees below the central arrow, indicate wind direction toward the HOTLINE.) The Equipment Drop Area (from left to right) is indicated by a rectangle with a circle below indicating the location of the Plastic sheet and a right pointing arrow to another rectangle divided by a diagonal line into the Decon Outer Garments area and the Remove Boot Covers and Outer Gloves area with a circle below indicating the location of a 10 gallon can. A dashed line cutting vertically through this rectangle indicates the HOTLINE. To the right of the HOTLINE, above the rectangle, two circles indicate the location of the Decon Solution and Water. Two arrows continue from the second divided Decon rectangle to a circle marked with an X that has an upward pointing arrow, that turns back toward the dashed HOTLINE to an area labelled Redress: Boot Covers and Outer Gloves, and crosses the dashed HOTLINE. Another arrow from the circle marked with an X continues to a rectangle indicating the area to Remove Boots/Gloves and Outer Garments (For Disposal and Off Site Decontamination) with a circle below indicating the location of a 32 gallon can. Another series of arrows pointing downward go to another rectangle, the Remove Mask final decon area.
aSource: Excerpted from Field Standard Operating Procedures for the Decontamination of Response Personnel {FSOP 7}. EPA Office of Emergency and Remedial Response. Hazardous Response Support Division, Washington. DC. January 1985. Which responder level is trained to enter heavily contaminated?Operations-level responders respond to hazardous materials and WMD incidents for the purpose of protecting nearby persons, the environment, or property from the effects of the release. Technician-level personnel are trained to enter heavily contaminated areas using the highest levels of personal protection.
What is the number of patients that generally serves as the lowest possible threshold for a multiple casualty incident?An MCI may be declared with fewer than 10 patients if the system is overwhelmed by that number. In other jurisdictions 20 or more patients might be an MCI.
Which of the following is the primary concern in any hazardous materials emergency?In ALL hazardous material emergency situations, the primary concern is the protection of personnel. The secondary concern is to confine the contamination, but ONLY if you are specifically trained under 29 CFR 1910.120 to do so.
How do you respond to a hazmat incident?Responding to HAZMAT Incidents: An Eight-Step Process. STEP 1: Site Management & Control. ... . STEP 2: Identifying the Problem. ... . STEP 3: Hazard & Risk Evaluation. ... . STEP 4: Protective Clothing & Equipment. ... . STEP 5: Information Management & Resource Coordination. ... . STEP 6: Implementing Response Objectives. ... . STEP 7: Decontamination.. |