Presentation on theme: "Non-Engineering Controls WM (Bill) Young CIH, CSP Sr. EH&S Specialist GEO Specialty Chemicals – Deer Park Operations Deer Park, Texas Friday July 27, 2007."— Presentation transcript:
Non-Engineering Controls WM (Bill) Young CIH, CSP Sr. EH&S Specialist GEO Specialty Chemicals – Deer Park Operations Deer Park, Texas Friday July 27, 2007 SWCOEH CIH Review Course GCS-AIHA
Non-Engineering Controls Hazards - Skin Administrative Controls PPE – Selection, Use, and Limitations – Glove Permeability – Eye Protection – CPC Hazards - The Lungs Respiratory Protection – Types of Respiratory Protection – Fit Testing – Breathing Air Specifications
Hazards - The Skin 1. 34% of all reported cases of chronic occupational diseases were dermatological disorders. a. It is a recognized health hazard and the major occupational health disease in the U.S. b. Dermatitis may be an indicator of more serious and insidious systemic exposures. c. There is a lack of published standards for safe levels of skin exposure. d. What is an acceptable level of dermal exposure?
2. The skin is potentially a significant route of exposure for systemic toxins. 3.Skin:largest organ in the body. a.10-15% of the body weight. b.1.8 square meters. c.temperature and water regulation. d.protection from the environment. 4.Made of two layers:epidermis, dermis and appendages:hair follicles sebaceous glands sweat glands.
5.Enzymes in the skin. 6.Barrier function of the skin. a. Stratum Corneum-matrix of lipids and corneocytes. b. Non-polar molecules penetrate more rapidly than polar molecules. Molecules soluble in both polar and non- polar solvents penetrate fastest. c. Appendageal transport-faster, yet less a problem. d. The skin is covered with a thin lipid based layer with pH of which offers limited buffering capacity to weak acids and alkaline solutions. e. Alteration of the barrier: (Alteration of the permeability of the stratum corneum) 1. Hydration-increases thickness and makes a larger membrane diffusion constant which leads to greater permeation. 2. Occlusion (by wearing PPE) yields to increase of temperature and hydration of the membrane producing greater permeation potential.
A. soles > palms > back of hand > scrotal/post auricular >scalp > arms, legs, trunk. 7. Membrane thickness and permeability: Highest to Lowest.
Administrative Controls Management Involvement Employee Training Rotation of Employees Air Sampling Bio-Sampling Medical Surveillance
PPE – Selection Chemical(s) Involved – Permeability – Penetration – Degradation Degree of Contact Toxicity Limitations Service Life - Usage/Decontamination/Disposal
CPC Use 1.The use of chemical protective clothing (CPC) has increased tremendously in the last decade. Why? A. Regulations and standards relying on use of PPE. B. The apparent cost effectiveness of use of PPE over engineering controls. C. The need for totally protective suits for asbestos removal, hazardous waste disposal sites, and others. 2. There was a false sense of security in the early days. "Use rubber gloves. It protects against all chemicals."
3.Where is protective clothing used today? Routine and Emergency Handling Situations a. Handling of liquid chemicals during manufacture. b. Maintenance and quality control for chemical processes. c. Acid baths and other treatments in electronic processes. d. Application of pesticides and other agri-chemicals. e. Chemical waste handling. f. Emergency chemical response. g. Equipment leaks and failures.
4.Does the CPC really provide the protection needed? a. The majority of workers with a potential for skin contact by hazardous materials are protected by some form ofchemically resistant clothing or gloves. These range in use from single latex gloves to totally encapsulating suits. b. In 1977: ASTM Committee F-23 1.ASTM TEST : Provides data on breakthrough time and rate as a steady state rate. 2. ASTM F : A standard battery of tests for 15 selected chemicals. 3. Additional testing was also started such as penetration and degradation tests which were primarily pass/fail tests. 4. The only guideline required by OSHA was 29CFR (c) which requires "all personal protective equipment shall be of a safe design and construction for the work to be performed".
CPC material weaknesses 1.CPC materials may allow chemicals to flow through to the inside surface of the material exposing personnel to the chemical agent. 2. CPC materials are made up of polymer chains of different types. Plasticizers are added to provide flexibility. 3. Material flow through the CPC material generally occurs as a result of three processes at the same time: Permeation Penetration Degradation
1.Permeation is a three step process The same process occurs when air leaves a balloon even though there are no obvious leaks. The air permeates the walls of the balloon and causes it to deflate. 2. Penetration is the bulk flow of chemical through zippers, stitched seams, pinholes or imperfections-the chemical is simply flowing through a hole in the CPC material. 3. Degradation is the deterioration of the chemical or physical structure of the CPC materials. The solvent may disintegrate or react with the polymer chains and/or plasticizers causing swelling and /or hardening. Solution Diffusion Evaporation
PPE – Use Why Use - + / - CPC, Gloves, Boots – Routine Intermittent Immersion – Preventive/Potential Levels of Protection – A, B, C, D
PPE - Construction Mono-layer vs. Multi-layer Unsupported vs. Supported Seals and Seams – Thermal – Glued – Stitched – Combinations Limitations
PPE – Limitations Chemical Task – Time and Exposure Conditions Abrasion Cuts and Punctures Flexibility Dexterity Other Issues
Production and Construction 1.Gloves a. Latex System: Handform into liquid rubber b. Solvent System: Handform into a rubber solvent mixture. Repeated to form layers. Covers up pinholes. c. Supported: when increased thermal, abrasion, or tear resistance is needed. d. Unsupported allows for greater dexterity. e. Flock lined. f. Different outer finishes allows for grip and handling g. Flat sheets may be joined by thermal seams.
2. Boots a. Until recently, boots were made of PVC or Rubber. Boots are more limited in materials due to the molding injection process. b. Boot processes 1. Single stage injection molding-soft sided rubber, rain boot appearance-the sole is the same material, but thicker. 2. Two stage injection molding process-PVC and PVC/Nitrile formulations. 3. Hand made boots-Neoprene. 4. Booties-made from many polymers.
3. CPC suits a.Flexible plastic or rubber film sheets, coated fabrics or laminates. b. Base materials of nylon, Dacron, Nomex, fiberglass. 1.Limited use and reusable (PVC). 2. Neese #45 Rolled process Neoprene on Nylon. 3. Limited use suits-Supported film or laminate Saranex coated Tyvek-Saran is applied to spunbounded Tyvek fabric. c. CPC suit materials are joined by either welding or stitching seams. 1. Welding-heat and pressure, added cost, no holes. 2. Stitching-Nylon thread, double seam, holes are sealed with glue or tape.
Eye and Face Protection Spectacles Face Shields – Chemical – Thermal – Particulates Goggles – Splash – Dust Welding Helmets and Handshields
HOW TO SELECT CHEMICAL RESISTANT GLOVES 1. IDENTIFY THE CHEMICAL(S) WITH WHICH YOU ARE WORKING 2. CONSULT THE MATERIAL SAFETY DATA SHEET 3. CHECK THE GLOVE MANUFACTURER'S CHEMICAL RESISTANCE GUIDE 4. ADDITIONAL CONSIDERATIONS GLOVE LENGTH SPLASH PROTECTION IMMERSION PROTECTION ABRASION RESISTANCE CUT RESISTANCE FLEXIBILITY OF GLOVE DEXTERITY REQUIRED 5. CHEMICAL MIXTURES ? ADDITIONAL TESTING MAY BE REQUIRED. CONSIDER DOUBLE GLOVING
BUTYL RUBBER (BR) Strengths-Resists medium polar organics, such as acetone, DMF, and pyridine. Moderate cut resistance to cuts, snags, punctures, and abrasion WeaknessesNot for use with pure hydrocarbons and chlorinated solvents. FLAT FILM StrengthsSuperior chemical and permeation properties. WeaknessesGloves lack dexterity and puncture easily. KEY CHARACTERSITICS OF COMMONLY USED CHEMICAL RESISTANT GLOVES
NATURAL RUBBER StrengthsProtects against bases, alcohols, and dilute solutions Performs fairly well with ketones and aldehydes. Resists cuts. WeaknessesSome chemical such as oils, greases, and organics can cause the gloves to swell and soften. NEOPRENE StrengthsWide range of uses such as oils, acids, caustics, and solvents. WeaknessesThe physical characteristics are generally inferior to nitrile and natural rubber, but can be improved with use of additives in certain glove designs. NITRILE StrengthsProtects against oils, solvents, esters, and grease. Resists snags, punctures, cuts, and abrasion. WeaknessesNot recommended for use in ketones and some organic solvents.
POLYVINYL ALCOHOL (PVA) StrengthsProtects against aliphatics, aromatics, chlorinated solvents, and ketones. Resists cuts, snags, abrasion, and punctures. WeaknessesDegrades in water and light alcohols POLYVINYL CHLORIDE (PVC ) StrengthsProtects against acids, caustics, alkalies, bases, and alcohols. Resists abrasion. WeaknessesNot recommended for use with some ketones and solvents which can wash plasticizers out of the glove. VITON StrengthsResists chlorinated and aromatic solvents, such as benzene, ethylene chloride, and carbon disulfide. WeaknessesNot for use with ketones, esters, and amines.
Types of Chemical Protective Clothing 1.Jacket 2.Pants 3.Coat 4.Bib Overall 5.Apron 6.Coveralls 7.Splash Suit
HAZMAT - Levels of Protection 1.Ensembles must be tailored to the specific situation in order to provide the most appropriate level of protection. Wearers must be qualified, trained on the hazards and the use of the equipment, and medically approved. a. Reasons to upgrade: 1. Known or suspected presence of dermal hazards. 2. Occurrence or likelihood of gas or vapor emission 3. Change in work or task will increase contact with hazardous material. 4. Request of the individual performing the task. b. Reasons to downgrade: 1. New information indicating the situation was less hazardous than was originally thought. 2. Change in conditions that decreases the hazard. 3. Change in work that will reduce contact with hazardous materials.
The Hot Zone - Based on … 2.LEVEL A - the highest level of protection, for skin, eye, and respiratory protection. a. To be used when: 1. The highest protection for skin, eyes, and respiratory system is required due to known chemical hazards of: a. High concentrations of vapors gases or particulates. b. High potential for splash, immersion or exposure to unexpected vapors, gases or particulates that are harmful or capable of being absorbed through the skin. 2. Substances with a high skin hazard are present. 3. Operations are to be conducted in confined, poorly ventilated, areas until it is determined that LEVEL A protection is not required.
Level A Continued b. Equipment. 1. Recommended: a. Pressure-demand SCBA or pressure-demand supplied full face respirator with escape SCBA. b. Fully-encapsulating, gas-tight, chemical resistant suit. c. Inner chemical resistant gloves. d. Chemical resistant safety boots/shoes. e. Two way radio communications. 2. Optional: a. Cooling unit. b. Coveralls. c. Long cotton underwear. d. Hard hat. e. Disposable glove and boot covers.
Level A Continued c. Limitations 1. Fully-encapsulation suit material must be compatible with the substances involved. Don’t forget the visor. d. Maintenance 1. The suit must be inflated periodically, per the manufacturer's recommendations, to test the air relief valves. It also has a periodic inspection. 2. It also must be inspected prior to use.
3.LEVEL B - Highest respiratory protection still maintained, but less skin protection. MINIMUM LEVEL FOR INITIAL ENTRY. a. To be used when: 1. the highest level for respiratory protection is required but less skin protection is appropriate: a. IDLH concentrations of substances that do not represent a skin hazard. b. levels do not meet the criteria for air purifying respirators. 2. Atmospheres with less than 19.5% oxygen. 3. Levels of substances may be incompletely determined, but not suspected to be at levels harmful to the skin contact or absorption
LEVEL B continued b. Equipment 1.Recommended: a. Pressure-demand SCBA or pressure-demand supplied full face respirator with escape SCBA. b. Chemical resistant clothing, one or two piece reusable or disposable. c. Inner and outer chemical resistant gloves. d. Chemical resistant safety boots/shoes. e. Two way radio communications. f. Hard hat. 2. Optional: a. Cooling unit. b. Coveralls. c. Long cotton underwear. d. Face shield. e. Disposable glove and boot covers.
Level B Continued c. Limitations 1. Only for gases or vapors not suspected to have substances harmful through skin contact or absorption. 2. Only for work in which it is highly unlikely that exposed skin will not be affected. 3. Suit material must be compatible with the substances involved. d. Maintenance 1. The suit must be inspected prior to use, per the manufacturer's recommendations.
4.LEVEL C - Same skin protection as LEVEL B, but less respiratory protection. a. To be used when: 1. atmospheric contaminants, liquid splashes, or other direct contact will not adversely affect the skin. 2. Air contaminant has be identified, concentration measured, and a canister is available that can remove the contaminant. 3. All criteria to use air purifying respirators are met.
LEVEL C continued b. Equipment 1. Recommended: a. Full face air purifying canister equipped respirator. b. Chemical resistant clothing, one or two piece reusable or disposable. c. Inner and outer chemical resistant gloves. d. Chemical resistant safety boots/shoes. e. Two way radio communications. f. Hard hat 2. Optional: a. Cooling unit b. Coveralls c. Long cotton underwear d. Face shield e. Disposable glove and boot covers. f. Escape respirator
LEVEL C continued c. Limitations. 1. Equipment must be compatible with the chemicals of concern. 2. Not adequate to be worn in the exclusion zone. 3. Atmosphere must contain 19.5% oxygen. d. Maintenance. 1. The suit must be inspected prior to use, per the manufacturer's recommendations. 2. Escape respirator must follow guidelines of respiratory protection program.
5.LEVEL D - Minimal skin protection. No respiratory protection. a. To be used when: 1. Atmospheres have no known hazards. 2. Work functions preclude splashes, immersion, or potential for unexpected inhalation or contact with hazardous levels of any substance. b. Equipment 1. Recommended: a. Coverall. b. Safety boots/shoes. c. Safety glasses or chemical splash goggles. d. Hard hat. 2. Optional: a. Gloves. b. Face shield. c. Cooling unit. d. Escape respirator.
LEVEL D continued c. Limitations. 1. Equipment must be compatible with the chemicals of concern. 2. Not adequate to be worn in the exclusion zone. 3. Atmosphere must contain 19.5% oxygen. d. Maintenance. 1. The suit must be inspected prior to use, per the manufacturer's recommendations. 2. Escape respirator must follow guidelines of respiratory protection program.
Decontamination and Reuse 1.Single use items need no laundering. But for routine exposure or highly toxic exposures requiring expensive fully encapsulating suits, decontamination and reuse may be critical. 2. Problems associated with decontamination a. Taking work clothing home for laundering could contaminate other people. b. Establishment of a toxic reservoir in elastomeric suits and gloves is possible. c. "Matrix release" of this trapped reservoir can be enhanced by liquid contact from body perspiration. d. Entrapment of a substance against the skin from chemicals that may have penetrated by pinholes, poorly sealed seams, or other material imperfection. 1. The protective garment may act as a barrier to increase the gradient for more movement of the liquid into the skin, thereby increasing the risk instead of reducing the risk.
3. The following are to be considered when evaluating the overall risk: a. Effects of reuse. b. Entry into atmospheres in which no dermal contact is acceptable. c. Potential garment failure. 4. The overall risk must be scrutinized with cost/benefit: Plainly expressed-the choice is between a $2.00 glove that leaks a little or a $12.00 glove that leaks a little less.
Selection process 1. Identify the process and the chemicals involved. a. Characteristics of the potential contact-splash or immersion. b. Physical properties required of the glove or garment flexibility, puncture or abrasion resistance, thermal protection. 2. Determine the degree of contact with the chemical agents. a. Exposure period-time of contact. b. Body part of exposure. 3. Determine the toxicity of the chemical: a. skin effects: corrosiveness, toxicity, physical damage, allergic reaction. b. inhalation hazards. c. oral ingestion toxicity. d. allergic potential. e. target organ effects - systemic. f. Additive or synergistic effect of inhalation or ingestion. g. (vapor pressure is also helpful)
4. Consider the limitations caused by wearing the CPC -sight, hearing, touch. 5.Determine the anticipated use - single or routine, associated costs, and acceptable exposure. 6.Determine user acceptance of CPC-field testing. 7.Consider OSHA or other regulatory requirements.
8. Review permeation data and test methods. Rule of thumb # degree C temp increase yields a 2 fold decrease in breakthrough time. Rule of thumb #2 - Double the thickness and breakthrough time is doubled a. Permeation Rate. How fast the material is "pouring" in. b. Breakthrough. 1. Vapor is coming through? So what? a. skin absorption potential to the vapor. b. condensation of vapor to liquid. c. permeation rate-high or low.
9. Determine service life of CPC. a. If the breakthrough time is greater than or equal to the job task time, the permeation rate is slow, toxicity is low and skin absorption is low, service life over a period of time could be calculated. number of uses = breakthrough time job task time SERVICE LIFE = number of uses/job frequency b. If breakthrough is less than the job task time the number required for the job task time is equal to job task time/breakthrough time. SERVICE LIFE= breakthrough time
Exposure assessment ASSESSING RISK FOR DERMAL PERMEATION 1.Gather data from: a. Actual work place exposures. b. Epidemiological studies. c. Clinic reports of toxic effects. d. Prospective bio-monitoring. e. Skin Permeation Studies. 1. End point biological tests. 2. Pharmacodynamic evaluation. a. Metabolism. b. Distribution. c. Excretion.
2. Breakthrough time and steady state permeation rate can be used to determine approximate dose. Dose=(Tc - Tb) ( J Ae) Dose = skin dose (mg) Tc = Chemical contact period in seconds Tb = Time to breakthrough in seconds J = Steady state flux of permeating chemical in mg/m2 per second Ae = Area exposed in square meters
3. Other Factors to Consider In Dose Estimation: a. Chemical mixtures. b. Quality of garment or glove. c. Physical state of the barrier (skin). d. Contamination or changes in the exposure period. e. Problems with decontamination. f. Difficulty of applying dermal dose estimation to the risk of systemic toxicity. 4. An OBVIOUS solution is use a material with total impermeability. But significant problems remain with the skin's ability to respire and body heat displacement.
Training 1. Why? a. Allows the user to become familiar with the equipment in a non-hazardous situation. b. Instills confidence in the equipment. c. Makes user aware of limitations and capabilities of the equipment. d. Increases efficiency of work and may increase protection. e. Reduces expense of PPE maintenance. f. Compliance
2. Initial training should include as a minimum: a. The proper use and maintenance of the selected PPE, including capabilities and limitations. b. The nature of the hazards and the consequences of not using the PPE. c. The human factors influencing PPE performance. d. Instruction inspecting, donning, checking, fitting, using and doffing. e. Respirator fit testing to ensure proper fit. f. Wear PPE for a long period in normal air, then wear PPE in test conditions, simulating a work effort. g. Responsibilities: decontaminating, cleaning, maintenance, and repair. h. Emergency procedures and self-escape in the event of a PPE failure. i. The buddy system. j. The site safety plan and the individual's role in an emergency.
Written PPE Program 1.Introduction a. The administration of the PPE program. b.Who has what responsibility. c. What regulations or corporate guidelines are resources 2.Selection a. The approval procedures and selection guidelines. b. Where the approved equipment is listed. c. Testing program. 3. Training: initial, review, visitor. a. User responsibilities. b. Inspections. c. Donning, doffing and emergencies. d. Limitations. e. Regulations. f. Maintenance, decontamination and laundering. g. Training frequency and documentation requirements.
4. Inspections a. Type of equipment, test method, frequency and who is responsible table. 5.Decontamination and disposal procedures. a. Location of procedures. b.Location of disposal and decontamination equipment. 6.Maintenance a.Lists equipment and authorized maintenance. b. Repair procedures. 7.Laundering a. Specifics about laundering services and procedures. b. Communication, e.g. MSDSs sent to the service.
8. Storage a.Where and how PPE is to be stored. b. Who is responsible. 9. Program Review frequency. 10. Approvals. 11. Table with approved PPE or task grid including specific equipment to be worn.
PPE - Respirators Lungs and Air Selection Types and Limitations of Respirators Donning, Doffing Storage and Maintenance
Lungs and Air 10 cu. meters/8 hrs or 20.8 LPM ~500 mL per breath Lung surface - 70 to 100 square meters Partial Pressures – sea level O mmHg, 8000 feet O mmHg – alveolar PO mmHg, PCO mmHg – pulmonary arteries PO mmHg, PCO mmHg Nasal passages, pharynx, larynx, trachea, bronchi, bronchial, alveoli
Respirators APFs and passing FF Positive Pressure vs. Negative Pressure SCBA - closed vs. open FF - air supplied, air purifying PAPR - air purifying HF - air supplied, air purifying Hood 1/4 mask
Types of Respirators Color Code vs. Type Particulates NRP non-oilresistantproof 99.97% 99% 95%
Respiratory – Fit Testing QNFT vs. QLFT Isoamyl Acetate Saccharin Solution Bitrex TM (Denatonium Benzoate) Solution Generated Aerosol – Corn Oil, PEG 400, DEHS, NaCL Portacount CNP banana oil => OV P-100 either
Breathing Air Specifications GRADE D – Oxygen: 19.5 to 23.5% – CO 2 : 1000 ppm – CO: 10 ppm – Particulates/Hydrocarbons: 5 ppm – Odor - Lack of Noticeable Odor – Dew Point: -10C (-50F)
Summary Non-Engineering Controls are the least preferred method of protecting employees ALL PPE has Benefits and Limitations – Rarely does PPE provide 100% Protection Temperatures, Exposures and Rules of Thumb Murphy’s Law Questions?