MSDSs

RESPIRATORY PROTECTION PROGRAM:
Requirements for Air-Purifying Respirators

I. OVERVIEW

A. Introduction. "I think we need respirators in our workplace; what do we do?"

First, we must establish whether you really need a respirator or whether the inhalation hazard can be controlled in another way. Respirators are considered a "last resort" protection against inhalation hazards. The Occupational Safety and Health Administration (OSHA) states: "In the control of those occupational diseases caused by breathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, sprays, or vapors, the primary objective shall be to prevent atmospheric contamination. This shall be accomplished as far as feasible by accepted engineering control measures (for example, enclosure or confinement of the operation, general or local ventilation, and substitution of less toxic materials)."

All feasible and accepted engineering control measures for preventing atmospheric contamination shall have been exhausted before turning to respirators for worker protection. If you have made that effort but suspect that atmospheric contamination is still a problem, call the Office for Research Safety (ORS). ORS will perform a hazard evaluation and advise you whether respirators or other engineering controls are needed.

Even when evaluation reveals that respirators are not required, some workers may want to wear them voluntarily if the principal investigator/supervisor agrees to this. In that case, depending on the type of respirator chosen, many of the regulatory requirements are the same as if respirators were required.

Section II guides you step-by-step through the process of evaluating the hazard, obtaining medical evaluation, selecting and fit testing respirators, and training wearers.

B. Responsibilities. Principal investigators and supervisors, respirator wearers, and administrative units have well-defined responsibilities under this program. The principal investigator (PI) or supervisor controls the conditions of the workplace. PIs or supervisors are responsible for initiating the respiratory protection process, overseeing proper use and maintenance of respirators and other equipment, initiating action when conditions change, following established schedules, and providing (paying for) respirators and associated supplies. Respirator wearers are responsible for adhering to procedures and following schedules, bringing changing conditions to the attention of the PI/supervisor, and caring for their equipment. ORS services include providing the general written respirator program (this document) and assisting with hazard evaluation, respirator selection, fit testing, training of respirator users, identifying medical evaluation providers and maintenance activities. Both PIs/supervisors and ORS must maintain some records.

C. Regulatory Background and University Policy. The respiratory protection program is required by the OSHA Standard for Respiratory Protection, 29 CFR 1910.134, which went into effect on April 8, 1998. University policy designates the PI/supervisor as the employer responsible for ensuring adherence to safety regulations and procedures. University policy is recommended by the Chemical and Biological Safety Committee and approved by the vice president for research.

D. Necessity for Respirators. Respirators are required if engineering controls are insufficient and the worker's exposure is expected to be above the permissible exposure limit (PEL¹) established by OSHA for the contaminant of concern. For compounds with no set PEL, professional judgment and scientific data steer the decision concerning the use of respirators. When a respirator is warranted, the PI/supervisor must select a respirator that will reduce the worker's exposure to a level below the concentration considered hazardous by the scientific literature.

E. Required versus Voluntary Use. The hazard evaluation will determine whether workers are required to wear respirators or whether engineering controls can eliminate the hazard. Even when it can be demonstrated that exposures are under the standard hazard limit (e.g., the PEL), some workers may choose to voluntarily wear a respirator. See section VI for further clarification of required and voluntary use. It is important to understand that many of the same requirements apply to voluntary wearers. These requirements are noted throughout this document. Appendix A provides additional information that should be given to voluntary wearers. The PI/supervisor will determine if voluntary use is acceptable or whether to make respirator use mandatory.

F. What PIs/Supervisors Need to Do on a Continuing Basis.

• Be aware of changing circumstances in the workplace that may affect the need for respirators, such as introduction of new processes or chemicals, increased use of given chemical volume, or alterations in the ventilation system. Call ORS for advice when you become aware of such changes.
• Be aware of changes in working conditions that may effect the ability of wearers to use respirators effectively, such as conditions of heat and humidity, significant change in the work effort, new protective clothing or equipment, or other environmental factors.
• Be aware of changes in wearers' physical ability to wear a respirator, such as growth of facial hair, dental work, new eyeglasses, changes in body weight, and so forth. If a worker reports medical signs and symptoms related to respirator use you must bring them to the attention of the healthcare professional for evaluation.
• Maintain surveillance of the work area and instruct respirator wearers to leave the work area a) to wash their skin and respirator as necessary to prevent irritation, b) if they detect breakthrough, changes in resistance or leakage, or c) to replace the respirator, filter, cartridge, or canister elements.
• Establish an inspection schedule to ensure that respirators are maintained in a clean and operable condition.
• Maintain a supply of appropriate cleaning and disinfecting supplies and establish a cleaning and disinfecting protocol.
• Ensure that respirator wearers perform a facepiece seal check each time they don the respirator.
• Adhere to the schedule for annual fit testing.
• Ensure respirators are properly stored between uses.

G. Cost. The PI/supervisor shall provide respirators, medical evaluations, fit testing, training, and all services and equipment associated with both voluntary and mandatory respirator use (e.g., replacement of defective parts, disinfecting solutions, storage bags, etc.) at no cost to the workers. As OSHA states, the obligation of the employer to pay the costs of the respiratory protection program should be "crystal clear."

H. Cleaning, Disinfecting, Maintenance and Repair. Routine cleaning, disinfecting, and maintaining respirators are the responsibility of the wearer under supervision of the PI/supervisor. See sections VIII and IX for more information on cleaning and disinfecting and a checklist for routine maintenance.

II. PROCEDURES FOR ACQUIRING A RESPIRATOR

Step 1: Hazard Evaluation. The first step is to perform, or have performed, a hazard evaluation to determine whether atmospheric contamination exceeds or is likely to exceed the hazard limit. ORS will perform the evaluation on request. ORS will work with you to find methods to reduce levels of atmospheric contamination. If such methods are not sufficient and respirators are required, proceed to the next step, medical evaluation of respirator wearers.

Step 2: Medical Evaluation. A physician or other licensed healthcare professional (PLHCP²) is required to determine whether or not a potential respirator wearer is physically able to wear a respirator without adverse health effects. Every worker must be medically evaluated prior to fit testing and before wearing a respirator.

Using a respirator may place a physiological burden on a worker that varies with the type of respirator worn, the job and workplace conditions in which the respirator is used, and the medical status of the individual. Respirator wearers may suffer from medical conditions (e.g., asthma, emphysema, heart disease, claustrophobia, and medications) that preclude safe use of a respirator.

Prior to the medical evaluation the PI/supervisor is responsible for completing Appendix B and providing it to the PLHCP. Appendix B provides the following information to the PLHCP:

• the type and weight of the respirator to be used by the worker
• the duration and frequency of respirator use
• the expected physical work effort
• additional protective clothing and equipment to be worn
• temperature and humidity extremes that may be encountered.

At the time of the medical evaluation the worker needs to complete the mandatory OSHA Respirator Medical Evaluation Questionnaire (Appendix C) and provide it to the PLHCP. The questionnaire is available from the Office for Research Safety. Follow-up medical evaluations may be required annually.

Make an appointment with a PLHCP. The following organizations or persons can provide medical evaluations:

Chicago Campus

• Northwestern Memorial Hospital Corporate Health, Galter Pavilion, 201 East Huron Street, 9th floor – Suite 240, Chicago, IL, phone (312) 926-8282. This is the University's designated healthcare provider for occupational illnesses and injuries. Be prepared to provide a CUFS number.

Evanston Campus

• University Health Service (students only). Be prepared to provide a CUFS number.
• OMEGA (Occupational Medicine-Evanston/Glenbrook Associates), 1000 Central Street, Suite 840, Evanston, IL, phone (847) 657-1700. OMEGA is the University's designated healthcare provider for occupational illnesses and injuries.

Contact ORS for more information about any of these options. The regulation requires that each PLHCP have a copy of the University's program and the OSHA regulation. ORS has already given them to the listed providers. If another provider is used, make they have the required documents. They may be obtained from ORS.

The PI/supervisor is required to ensure that both the questionnaire and the medical evaluation are to be administered confidentially during the worker's normal working hours or at a time and place convenient to the worker. The PI/supervisor shall also ensure that the worker has an opportunity to discuss the questionnaire and/or medical evaluation results with the PLHCP.

Following the review of the questionnaire and/or examination of the worker, the PLHCP must submit a written recommendation regarding the worker's ability to use the respirator to the PI/supervisor. The recommendation may contain only the following information:

• any limitations on respirator use related to the medical condition of the worker, or relating to the workplace conditions in which the respirator will be used, including whether or not the worker is medically able to use the respirator
• the need, if any, for any follow-up medical evaluations
  
• a statement that the PLHCP has given the worker a copy of the written recommendation concerning the evaluation.

Step 3: Respirator Selection. After receiving medical clearance for respirator use, make an appointment with ORS. At this meeting ORS will advise you on the types of respirators to purchase. It is the PI/supervisor's responsibility to provide, and pay for, all personal protective clothing and equipment, including respirators.

Step 4: Fit Testing. Fit testing is required before the worker first wears the respirator and annually thereafter. Call ORS to make an appointment for fit testing. Repeat fit testing may be required if the respirator wearer or PI/supervisor notices changes in the wearers' physical condition that could affect fit, and if a different facepiece is used. There is no charge for fit testing by ORS. While not required for voluntary wearers, fit testing is recommended.

Step 5: Training. Following fit testing, each wearer must receive basic respirator training from ORS. Training is offered at the time of fit testing or on a scheduled basis. Voluntary wearers are not required to be trained except for the information in Appendix A, however ORS recommends they receive the standard training.

III. TYPES OF RESPIRATORS

A. Air-Purifying Respirators. Ambient air is passed through an air-purifying element (filter, cartridge, canister) that removes the specific contaminants (particulates, vapors, and gases). There are two subdivisions of this category.

1. Negative-pressure air-purifying respirator: Air is passed through the air-purifying element by means of the breathing action of the wearer. Air pressure inside the respiratory inlet covering is negative during inhalation with respect to the ambient air pressure.
2. Powered air-purifying respirator (PAPR): Air is passed through the air-purifying element by means of a battery-powered blower.

Within the category of negative-pressure air-purifying respirator, there is a further subdivision. Such a respirator may be a filtering facepiece (traditionally known as a dust or dust-, mist-, fume mask) or a facepiece equipped with replaceable filters, cartridges, or canisters. The filtering facepiece is a negative-pressure particulate respirator with a filter as an integral part of the facepiece or with the entire facepiece composed of the filtering medium.

A facepiece with separate, replaceable filtering elements is a tight-fitting respirator that forms a complete seal with the face. For the purposes of this document, filtering facepieces are not considered to be tight-fitting respirators.

The PI or supervisor shall provide a National Institute for Occupational Safety and Health (NIOSH) certified air-purifying respirator. This means that the respirator meets the stringent testing conventions of NIOSH 42 CFR Part 84, the final rule for Respiratory Protective Devices. See Section V for an explanation of the certification elements. The respirator must be used in compliance with the conditions of its certification.

• Failure to use and maintain the respirator properly could result in injury.
  
• Do not exceed the maximum use concentrations established by regulatory standards.
  
• Never substitute, modify, add, or omit parts. Use only exact replacement parts in the configuration specified by the manufacturer.

B. Atmosphere-Supplying Respirators. Atmosphere-supplying respirators supply a respirable atmosphere independent of the workplace atmosphere. These units provide protection against toxic and oxygen-deficient atmospheres. The different types within this category are classified according to the method by which the breathing gas is supplied and the method applied to regulate the gas supply. A self-contained breathing apparatus (SCBA) is one example in this category. With SCBA units, the respirable gas source is carried by the wearer.

Atmosphere-supplying respirators are required in environments that are immediately dangerous to life or health (IDLH). IDLH refers to an atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere. This includes situations such as these:

• A short, one-time exposure (i.e., acute exposure) to a given compound above its IDLH value may cause death or irreversible adverse health effects immediately, within a few hours or a few weeks. For example, a single exposure to life-threatening or health-impairing concentrations of fluorides or cadmium fumes would be termed IDLH even though death or impairment might not occur until days or weeks after the exposure. It is not the length of the latency period that defines a concentration as IDLH; rather, it is the potential to cause that effect after only one exposure.
  
• Atmospheres that can effectively incapacitate an individual in the short-term are IDLH. For example, an atmosphere contaminated with a severe eye irritant may prevent an employee from escaping the space in time to avoid more serious health consequences.
  
• OSHA offers no differentiation between "potential" IDLH atmospheres and actual ones. If there is a possibility that the concentration of the dangerous substance cannot be controlled below life-threatening or health-impairing levels, it is deemed IDLH regardless of whether an inadvertent hazardous spill or release occurs.

Workers should have the training and capability to evacuate a workplace before exposure concentrations reach IDLH levels. The same is true for materials that displace oxygen. If normal workplace ventilation is maintained during an unplanned release of nitrogen or helium, workers should be trained to recognize the hazard and have sufficient time to exit the workplace before an oxygen-deficient (less than 19.5% by volume) atmosphere can result.

For those who work with highly toxic gases³ (such as arsine and phosphine, for example), training in evaluating the hazard is not sufficient. The IDLH limits for these materials are extremely low. Any unplanned release will likely exceed IDLH concentrations. Thus, in addition to worker training, toxic gas alarm systems should be available and operating properly to ensure early notification of lab occupants. They must have the opportunity to escape the environment promptly.

If you determine that atmosphere-supplying respirators will be necessary in your workplace (e.g., for emergencies or potential escape from toxic conditions), consult ORS. ORS is available on a 24-hour basis, every day for emergency response. If you anticipate emergencies of such a nature as to require air-supplying units, we encourage you to rely on our fully-equipped team instead of acquiring this specialized equipment yourself. These types of specialized units involve intense maintenance and training.

C. Additional Resources for Understanding Respirator Design and Function. More information about respirator types is available in the NIOSH Guide to Industrial Respiratory Protection, 1987, or the American National Standards Institute (ANSI) "Standard for Respiratory Protection," ANSI Z88.2-1992. Copies of these references are available for viewing in ORS.

IV. SELECTION OF THE PROPER RESPIRATOR

A. Guidelines for Selection. In general, selection of the proper respirator shall be based on:

1. the nature of the hazardous operation
2. the character of the respiratory hazard
   • physical properties of expected contaminants
     
   • oxygen deficiency
     
   • adverse effects of expected contaminants on the body
     
   • concentration of the contaminant (determined through informed professional judgment or exposure monitoring)
     
   • magnitude of the hazard under normal conditions of use and in reasonably foreseeable emergency conditions
     
   • established exposure limits set by OSHA, American Conference of Governmental Industrial Hygienists (ACGIH), and NIOSH
3. the location of the hazardous area in relation to the nearest area having safe, respirable air of acceptable quality
4. the period of time during which respiratory protection must be worn
   
5. the activities of the wearer
   
6. the physical characteristics, functional capabilities, and limitations of the various respirators under consideration
   
7. the assigned protection factor (APF) for the given type of respirator to be worn. An APF is the expected level of respiratory protection that would be provided by a properly functioning respirator when worn by a properly fitted and trained user. Depending on the respirator, the APF is a magnitude of protection (10×, 100×, etc.) over the OSHA PEL (or other applicable concentration limit when there is no PEL) afforded by the protecting device.

Should you find that you cannot identify or reasonably estimate the worker exposure, the atmosphere will be classified as IDLH by default, and entry would require the use of atmosphere-supplying respirators.

B. Limitations of Air-Purifying Respirators That May Disqualify Them From Use.

1. General Limitations
   • No protection is provided against absorption of chemicals through the skin, nor against skin irritation.
     
   • These respirators do not protect against oxygen-deficient atmospheres. They are designed only to neutralize or remove contaminants from the air.
     
   • The maximum contaminant concentration for which protection is offered is limited by the design efficiency and capacity of the air-purifying element (filter, cartridge, and canister).
     
   • The time period over which protection is offered is dependent on the type of air-purifying element, the concentration of the contaminant, humidity levels in the ambient air, and the wearer's respiratory rate.
     
   • The facepiece must be fitted carefully to the wearer's face to prevent inward leaks.
2. Specific Limitations
   • Quarter- and half-face respirators offer no protection against eye irritation.

V. AIR-PURIFYING ELEMENTS

A. General Warning. If the wearer is uncertain that the respiratory protection chosen for a particular inhalation hazard is satisfactory, the appropriateness of that protection should be verified by the PI/supervisor, ORS, and/or the manufacturer of the respirator. Use of an incorrect air-purifying element or respirator (i.e., air-purifying versus supplied air) will negate the expected protection against potential health hazards!

B. Particulate-Filter Units. The NIOSH 42 CFR Part 84 regulation provides for nine classes of particulate filters: three levels of filter efficiency, each with three categories of resistance to filter efficiency degradation. The three levels of filter efficiency are 95%, 99%, and 99.97%. The three categories of resistance to filter efficiency degradation are labeled N, R, and P.

1. Filter Efficiency. Filter efficiency is the stated percentage of particles removed from the air. Selection of filter efficiency (i.e., 95%, 99%, or 99.97%) depends on how much filter leakage can be accepted. Higher filter efficiency means lower filter leakage.
   
   NIOSH states that filters certified under 42 CFR Part 84 can be selected without regard to particle size. All filters tested under the approved procedures will be effective against any size aerosol.
2. Filter Efficiency Degradation. Filter efficiency degradation is defined as a lowering of filter efficiency or a reduction in the ability of the filter to remove particles as a result of workplace exposure.
   
   The selection of N-, R-, and P-series filters depends on the presence or absence of oil particles, as follows:
   • if no oil particles are present in the work environment, use a filter of any series (i.e., N-, R, or P-series)
   • if oil particles (e.g., lubricants, cutting fluids, glycerine, etc.) are present, use an R- or P-series filter NOTE: N-series filters cannot be used if oil particles are present.
   • if oil particles are present and the filter is to be used for more than one work shift, use only a P-series filter

   To help remember the filter series, this simple guide is useful.

   • N is for Not resistant to oil
   • R is for Resistant to oil
     
   • P is for oil-Proof
3. Selection Guide for Particulate Filters.
   • Identify the aerosol contaminants and form (oil or non-oil)
     
   • Determine the expected concentration of air contaminants. Do not use these guidelines if the following situations exist.
     1. unknown contaminant concentration
     2. contaminant concentration is at or above the IDLH value for that contaminant
     3. oxygen concentrations are below or may fall below 19.5%
   • Determine the hazard ratio (HR) for all substances. The HR is the ratio of the air concentration of the hazardous contaminant(s) divided by the occupational exposure limit.
     1. If the highest HR is less than or equal to 10, use either a half- or full-face respirator.
     2. If the highest HR is between 10 and 50, use a full-face respirator.
        
     3. If the highest HR is greater than 50, another type of respirator must be selected.
   • Determine the filter efficiency required.
     1. Use a class 100 (99.97% efficiency) filter if required by a specific regulation or regulatory policy.
        
     2. If no such regulation or policy exists, use a class 95 (95% efficiency) filter.
   • Determine the filter series needed.
     1. If no oil is present, use a N-, R-, or P-series filter.
        
     2. If oil is present, use a R- of P-series filter.
        
     3. R-series filters must be changed after 8 hours of use or after the respirator is loaded with (exposed to) 200 mg of aerosol.
        
     4. Where oil is suspected but air samples have not been collected to determine its presence, use a R- or P-series filter.
   • Identify workplace and respirator characteristics to choose the most appropriate respirator within the specific filter class you have selected. Consider:
     1. maintenance capabilities
        
     2. fit
        
     3. compatibility with other PPE
        
     4. durability
        
     5. breathing resistance/wearer acceptance

C. Chemical Cartridges: Gas and Vapor Contaminants.

1. Acidic (acid gases). Substances that are acids or that react with water to produce an acid. In water, they produce positively charged hydrogen ions (H+) and a pH of less than 7. They taste sour and many are corrosive to tissues (e.g., hydrogen chloride, sulfur dioxide; hydrogen sulfide - escape only).
   
   NOTE: Air-purifying respirators are not appropriate for all acid gases. For example, fluorine is classified as being acidic; however, due to its poor warning properties, supplied air is the warranted protection. Hydrogen cyanide is characterized by a very low IDLH and thus requires supplied air. Air-purifying respirators with custom filters are rated as adequate protection for chlorine dioxide but the full-face respirator is recommended. Air-purifying respirators with filters for protection from hydrogen sulfide are only good for short duration exposures and should not be used as PPE for worker protection.
2. Alkaline. Substances that are bases or that react with water to produce a base. In water, they result in the production of negatively charged hydroxyl ions (OH-) and a pH greater than 7. They taste bitter and many are corrosive to tissues (e.g., ammonia, methylamine, butylamine, ethylamine).
   
   NOTE: Within the category of alkaline substances, air-purifying respirators are appropriate only for ammonia and certain amines (usually the same cartridge, check manufacturer's specifications). Other alkaline compounds such as stibine, phosphine and arsine (all hydrides) require the use of supplied air systems.
3. Mercury Vapor. A specialized cartridge is available to protect wearers against mercury vapors.
4. Organic (organic vapors, OV). Compounds that are composed of carbon and hydrogen. These include aliphatic hydrocarbons, alcohols, ethers, ketones, organic acids, nitriles, amines, aldehydes, aromatics, and cyclic ethers and epoxides. In the various groups, there may be compounds for which OV cartridges are satisfactory and ones which necessitate the use of supplied air equipment. Care must be exercised in selecting the proper protection.

   Organic compounds also encompass halogenated organics (1,1,1-trichloroethane, chloroform, carbon tetrachloride), amides (formamide) and isocyanates (toluene diisocyanate). Many of these compounds have poor warning properties and thus, OV cartridges are unacceptable or extremely limited in protection capacity.

5. NIOSH-Prohibited Cartridges. NIOSH prohibits the use of chemical cartridges for the following chemicals because of their toxicity, poor warning properties, reactivity or other hazardous characteristics:

D. Combination Filters. In the event that a worker will be exposed to particulates and gases and vapors, combination cartridges are necessary because neither type is adequate for the other contaminant class (i.e., a particulate filter will not afford protection against gases and vapors).

VI. REQUIRED VERSUS VOLUNTARY USE

A. Distinction Between Types of Use. The OSHA standard makes a distinction between required and voluntary use of respirators. A worker is required to wear a respirator in any workplace where respirators are necessary to protect the worker's health or where the employer has established a policy that respirators are required. In the case of voluntary respirator use, an employer may provide respirators at the request of workers or permit workers to use their own respirators. However, voluntary use is permissible only if the employer determines that a voluntarily worn respirator does not in itself create a health hazard.

B. Voluntary Use Responsibilities. There are two situations of voluntary use:

1. The great majority of voluntary use situations involve filtering facepieces which are provided for the worker's sense of comfort. For example, some individuals with allergies to research mice or rabbits may request a respirator when handling these animals. A worker sweeping a dusty floor may want a filtering facepiece.
   
   If the worker is provided a filtering facepiece, there are some minor requirements for the PI/supervisor to follow.
   
   • Use of the filtering facepiece may not interfere with the worker's ability to work safely.
     
   • The PI/supervisor must ensure that the filtering facepiece is not dirty or contaminated.
     
   • The PI/supervisor must provide the wearer with the information presented in Appendix A.
2. In some rare cases, a worker may wish to wear a tight-fitting facepiece with separate filtering elements. If this voluntary practice is permitted, there are additional requirements.
   • The PI/supervisor must determine that the worker is medically able to wear the respirator. The respirator may not adversely affect the wearer's health. A medical evaluation is a prerequisite to use.
     
   • The employer must ensure that the respirator is maintained in proper condition. This is essential to prevent exposure to contaminants that accidentally may have soiled the interior of the respirator and to avoid skin irritation and dermatitis associated with use of an unclean respirator. See sections VIII and IX for cleaning, disinfecting, and storage requirements.
     
   • Apply any other respiratory program rules necessary to guarantee that the wearer is not harmed.

    

VII. PROPER USE OF RESPIRATORS

A. Foundations of Proper Use. There are three primary rules the PI/supervisor must enforce to ensure the correct and effective use of respirators.

1. Prohibit conditions that may result in facepiece seal leakage.
   
2. Prevent workers from removing the respirators in hazardous environments.
   
3. Take action to achieve continued efficient respirator operation during the work shift.

B. Impediments to Facepiece Seal Protection. Do not permit tight-fitting facepieces to be worn by workers with:

1. facial hair that comes between the sealing surface of the facepiece and the face or that interferes with valve function
   
2. any condition that interferes with the facepiece-to-face seal or valve function
   
3. corrective glasses or goggles or other personal protective equipment that could interfere with the facepiece-to-face seal.

C. User Seal Check. The individual who will be using a tight-fitting facepiece must perform a user seal check to demonstrate that an adequate seal is achieved each time the respirator is put on. The user shall follow the positive and negative pressure checks listed below or the respirator manufacturer's recommended user seal check method prior to entering a hazardous atmosphere with the respirator. If you choose to adopt the manufacturer's procedures, you must prove that this method is equally as effective as the pressure checks explained here.

1. Positive Pressure Check.
   1. Close off the exhalation valve by lightly placing a palm over the exhalation cover. For many respirators, this method of leak testing requires the wearer to first remove the exhalation valve cover before blocking off the exhalation valve. The cover is then replaced after the test.
      
   2. Gently exhale into the respirator and create a slight positive pressure.
      
   3. Once you feel pressure in the facepiece, use your free hand to check around the outer fringes of the facepiece for leakage.
      
   4. Do you detect an opening? If so, the respirator must be readjusted to seal more firmly to your face. The positive pressure check is repeated until the build-up of a slight positive pressure inside the respirator is not accompanied by outward leakage.
2. Negative Pressure Check.
   1. Close off the inlet opening for the filter, cartridge or canister. This is done by covering the opening with the palms of your hands or by replacing the filter seals. The design of the inlet opening of some cartridges cannot be covered effectively with the palm of the hand. The test can also be performed by covering the inlet opening with a thin latex or nitrile glove or a piece of paper.
      
   2. Inhale gently so that the facepiece collapses slightly and hold your breath for approximately 10 seconds.
      
   3. As the facepiece remains slightly collapsed toward your face, pay attention to any potential leaks. You should not detect any inward leakage of air into the respirator if the seal is satisfactory.
      
   4. Do you detect a leak? If so, the respirator and/or the harness straps must be readjusted to seal the facepiece more firmly to your face. The negative pressure check is repeated until no leakage is perceived.
3. An adequate fit MUST be achieved before the wearer may enter a hazardous atmosphere! The user seal checks are not a substitute for the yearly fit test.

D. Continuing Respirator Effectiveness. On an ongoing basis, the PI/supervisor is responsible for evaluating the continued effectiveness of the respirators.

1. Maintain surveillance over the work area conditions and worker exposure and stress.
2. Allow respirator wearers to leave the work area:
   • to wash their faces and facepieces as necessary to prevent eye or skin irritation associated with respirator use
     
   • if they detect vapor or gas breakthrough, changes in breathing resistance, or leakage of the respirator
     
   • to replace the respirator or the filter, cartridge, or canister elements
3. If a worker detects vapor or gas breakthrough, changes in breathing resistance, or leakage of the facepiece, replace the respirator before allowing the worker to return to the work area.

VIII. CLEANING AND DISINFECTING

The respirator provided to a potential wearer must be "clean, sanitary, and in good working order." The following procedures are required to clean and disinfect respirators, unless the respirator manufacturer recommends another method which is proven to be equally effective. The PI/supervisor must maintain documentation that confirms that the manufacturer's procedures are as satisfactory as those given by OSHA. The methods utilized for cleaning and disinfecting must not cause damage to the respirator or harm to the user.

A. Cleaning Schedule.

1. A respirator issued for the exclusive use of one worker is to be cleaned and disinfected as often as necessary to be maintained in sanitary condition.
   
2. Respirators issued to more than one worker are to be cleaned and disinfected before being worn by different individuals.

B. Cleaning Procedures.

1. Remove filters, cartridges, or canisters. Disassemble the facepiece to the extent instructed by the manufacturer. Discard or repair defective parts.
   
2. Wash components in warm (maximum 110° F) water with a mild detergent or with a cleaner proposed by the manufacturer. A stiff bristle (not wire) brush may be used to facilitate the removal of dirt.
   
3. Rinse components thoroughly in clean, warm, preferably running water. Drain.
   
4. If the cleaner does not contain a disinfecting agent, immerse the respirator components in one of the disinfectants listed below for at least two minutes.
   • hypochlorite solution (50 ppm chlorine)
     
   • aqueous solution of iodine (50 ppm)
     
   • other disinfectants approved by the manufacturer that are equally potent
5. Repeat step 3 if step 4 was implemented.
6. Air-dry or hand-dry with a clean lint-free cloth.
   
7. Reassemble the facepiece, replacing the filtering elements.
   
8. Test the respirator to verify that all components work properly.

The importance of thorough respirator rinsing cannot be overemphasized. Detergents or disinfectants that dry on facepieces may result in dermatitis. In addition, some disinfectants may cause deterioration of rubber or corrosion of metal parts if not completely removed.

IX. STORAGE AND INSPECTION

All respirators must be properly stored to protect them from damage, contamination, dust, sunlight, extreme temperatures, excessive moisture, and disintegrating chemicals. Pack and store respirators to prevent deformation of the facepiece and exhalation valve.

A. Basic Inspection Before Each Use. All respirators used in routine situations shall be inspected prior to each use and during cleaning. The inspection must include the following points:

1. Check respirator function, tightness of connections, and the condition of the various parts (e.g., facepiece, head straps, valves, filtering elements).
   
2. Check elastomeric parts for pliability and signs of deterioration.

B. Identification of Filters, Cartridges, and Canisters.

1. Ensure that all filters, cartridges, and canisters used in the workplace are labeled and color coded with the NIOSH approval label. The label must not be removed and must remain legible.
   
2. The air-purifying element must be appropriate for the form of the contaminant to which the worker is exposed. A filter designed to remove particulates would not be adequate for protection against gases and vapors.
   
3. Identify and adhere to the end-of-service-life of the filtering element. See section C below.
   
4. Do not allow interchange of filters between brands of respirators. For example, a Scott respirator is only certified by NIOSH when used in conjunction with filters manufactured by Scott. A 3M filter on a Scott respirator would violate the NIOSH approval conditions.

C. Filter Service Life. Filters intended for removal of gases and vapors may be equipped with NIOSH-approved end-of-service-life indicators (ESLIs) warning that the sorbent is approaching saturation and is no longer effective.

For filters without ESLIs, the employer must enforce a sorbent change schedule based on reliable information and service life of the cartridges and canisters available in the workplace. The respirator manufacturer or chemical supplier should be able to provide guidance for developing the filter change schedule.

If the manufacturer cannot provide data, information, mathematical models, or suggestions to support the use of the given filter against the contaminants in your workplace, you must use atmosphere-supplying respirators.

D. Routine Inspection and Maintenance Checklist

Before wearing the respirator, always follow these steps:

1. Inspect the facepiece.
   • There should be no cracks or pits in the sealing edge. The facepiece should not be distorted or deformed in any way.
     
   • Rubber or elastomeric parts must be inspected for pliability and signs of deterioration. Stretching and manipulating rubber or elastomeric parts with a massaging action will keep them flexible and supple and will prevent them from assuming a deformed shape during storage.
2. Check the cartridge holders.
• The cartridge holders should be securely attached to the facepiece. A good seal will prevent leakage of contaminants into the respirator.
  
• The threads on the inside of the holder should not be chipped or cracked.
  
• The rubber gasket must be firmly in place.
3. Locate the inhalation valve.
   • The valve must be in place and in good condition. The user should ensure that it can be moved freely. A torn or warped valve should be replaced. A quick and easy test to establish the condition of the valve is to remove it and lay it on a flat surface. If the valve buckles and a wave in the rubber is noticeable, the valve must be discarded.
4. Locate the exhalation valve.
   • Check the cover of the exhalation valve for cracks or splits.
     
   • Remove the cover to inspect the valve itself. The valve should be free of tears. Stretch the rubber and look for pinholes.
     
   • Check the valve seat for scratches, holes or pits. There should be no foreign material on the seat and the valve must lie flat against it.
     
   • The cover should be able to spin freely over the valve.
5. Examine the head harness and buckles.
   • The serrations on the straps of the head harness should not be worn or smooth.
     
   • The buckles must work properly. They should not be bent
6. Choose the appropriate air-purifying element.
   • Is the air-purifying element designed to protect the wearer against the expected hazards? Verify that the element will remove the contaminants present in the environment in which the wearer is working.
     
   • The air-purifying element should not be used if it is dented or deformed.
     
   • It must be screwed tightly into position.

In addition, for full-face respirators:

7. Check the lens and the lens ring.
   • There should be no marks on the lens that would hinder vision.
     
   • The lens should not be marred with cracks or pits.
     
   • The lens should be seated properly in the facepiece.
     
   • There should be no gaps or bulges in the rubber around the lens. Both halves of the lens ring should be present and tightly fitted to one another.
8. Inspect the speaker diaphragm.
   • The grille on the speaker diaphragm should be located on the upper half of the unit, closest to the lens ring.
     
   • The diaphragm should not be cracked.
     
   • It must be held fast by a clamp. The adjuster screw securing the clamp should be in the five o'clock position.

When wearing the respirator, if a peculiar taste or odor can be noticed, the air-purifying element must be replaced. If the wearer encounters difficulty breathing, the air-purifying element should be replaced as well. In general, it is wise to keep track of hours of use for air-purifying elements since you must discard them in accordance with the filter change schedule. Be aware that certain cartridges are harmed by conditions of high humidity or excess dryness.

X. REQUIRED TRAINING

Before using a respirator, a worker shall be informed about the various types available and the conditions under which the respirator should be used. All instructions and cautions provided through worker training and the written respiratory program must be strictly followed. All users should become familiar with the OSHA standard and information about the contaminants present.

1. Required Use. Before wearing a respirator, each worker who is required under the standard or by the PI/supervisor to wear a respirator should be provided:
   • the reasons why they need respiratory protection
     
   • the nature, extent, and effects of respiratory hazards to which they may be exposed
     
   • an explanation of why engineering controls are not being applied or are not adequate and what effort is being made to reduce or eliminate the need for respirators
     
   • an explanation of why a particular type of respirator has been selected for a specific hazard
     
   • an explanation of the operation, capabilities and limitations of the respirator selected
     
   • instruction in inspecting, donning, checking the fit of, and wearing the respirator
     
   • an opportunity for each respirator wearer to handle the respirator, learn how to don and wear it properly, check its seals, wear it in a safe atmosphere, and wear it in a test atmosphere
     
   • an explanation of proper maintenance and storage
     
   • instruction in how to use the respirator effectively in emergency situations, including situations in which the respirator malfunctions
     
   • instructions in how to recognize the medical signs and symptoms that may limit or prevent the effective use of respirators
     
   • an explanation of the general requirements of the OSHA standard for respiratory protection.
2. Voluntary Use. Workers who voluntarily wear a respirator and who are not required by their PI/supervisor or the OSHA standard to wear a respirator must receive the basic advisory information on respirators provided in Appendix A.
3. Retraining/Special Training. Respirator users should be retrained annually, and when the following situations occur:
   • changes in the workplace or the type of respirator render previous training obsolete
     
   • inadequacies in the worker's knowledge or use of the respirator indicate that the worker has not retained the requisite understanding or skill, or
     
   • any other situation arises in which retraining appears necessary to ensure safe respirator use

APPENDIX A

INFORMATION FOR EMPLOYEES USING RESPIRATORS WHEN NOT REQUIRED UNDER THE STANDARD

Respirators are an effective method of protection against designated hazards when properly selected and worn. Respirator use is encouraged, even when exposures are below the exposure limit, to provide an additional level of comfort and protection for workers. However, if a respirator is used improperly or not kept clean, the respirator itself can become a hazard to the worker. Sometimes, workers may wear respirators to avoid exposures to hazards, even if the amount of hazardous substance does not exceed the limits set by OSHA standards. If your PI/supervisor provides respirators for your voluntary use, or if you provide your own respirator, you need to take certain precautions to be sure that the respirator itself does not present a hazard.

You should do the following:

1. Read and heed all instructions provided by the manufacturer on use, maintenance, cleaning and care, and warnings regarding the respirator's limitations.
   
2. Choose respirators certified for use to protect against the contaminant of concern. The National Institute for Occupational Safety and Health (NIOSH) of the U.S. Department of Health and Human Services, certifies respirators. A label or statement of certification should appear on the respirator or respirator packaging. It will tell you what the respirator is designed for and how much it will protect you.
   
3. Do not wear your respirator into atmospheres containing contaminants for which your respirator is not designed to protect against. For example, a respirator designed to filter dust particles will not protect you against gases, vapors, or very small solid particles of fumes or smoke.
   
4. Keep track of your respirator so that you do not mistakenly use someone else's respirator.

APPENDIX B

MEDICAL EVALUATION FOR RESPIRATOR USE

APPENDIX C

OSHA RESPIRATOR MEDICAL EVALUATION QUESTIONNAIRE

The Office for Research Safety provides appendices B and C as printable PDF files to maintain their formatting.

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