Periodically this newsletter shares some of our recent fit testing experiences which reinforce the need for periodic fit testing and refresher training.

Recently a new client called to inquire about fit testing an employee who recently complained of contaminant leakage into his respirator. The employee was referred to our clinic where respirator training was provided. After training, the employee began the process of selecting the most comfortable respirator from three sizes available for the make and model preferred by his employer. During this comfort selection process the employer felt our large full facepiece was significantly more comfortable, and fit better than the medium facepiece initially provided by his employer. Fit testing for this large facepiece resulted in a passing fit factor of approximately 10,000.

When the employee returned to work he was issued a large full facepiece respirator consistent with our recommendation. A few days later the employer called again and informed us the employee once again detecting respirator leakage when working in the contaminated area.

One of our staff (Jeff Bradley) went to the work site to confirm the proper make, model, style, and size facepiece was actually issued. The employee was asked to don the facepiece and perform user seal checks. During performance of the user seal check, leakage was detected by the employee and our staff member. The employee had visually inspected the facepiece prior to our visit and had not detected any damage. A more thorough inspection was then conducted by our staff, at which time two o-rings were found behind the speaking diaphragm (only one should be present). Apparently, a previous user had returned this respirator into service after mistakenly inserting an additional o-ring. Once the problem was identified and resolved, the employee successfully passed user seal check procedures and fit testing with this respirator.

This situation enforces several aspects of a comprehensive respirator program. First, proper training and performance of user seal checks permitted this employee to detect respirator leakage. Second, it is known that when respirators are disassembled, cleaned, reassembled, inspected, and returned to a storage, not all leakage may be detected by visual inspection. Fit testing employees in their own respirator may help identify leaks not recognized during user seal check procedures. Functional integrity tests can also be used to ensure respirators function acceptably. Finally, a well trained fit test operator can help resolve many respirator leakage problems.

Soon summer weather will return. When it does, many of us will need to switch to our summer-time cartridge change out schedules to accommodate the increased relative humidity that the summer season brings. According to 29 CFR 1910.134(d)(3)(iii)(B)(2), when there is no end of service life indicator available, the employer must change out chemical cartridge respirators based upon "objective information or data" to ensure cartridges are changed before the end of their service life. In other words, odor and taste should NOT be used as the sole basis for changing a chemical cartridge. While many factors affect cartridge service life (level of exposure, breathing rate, etc.), few can have as much effect as changes in relative humidity. The effect of humidity is greatest for low boiling point organic solvents at low concentrations. For example, when humidity is high (such as in the summer) you may need to change a
cartridge 10 or 15 times sooner than at other times of the year. As the contaminant concentration increases, the effect of humidity is of lesser importance. If you need training on cartridge change out schedules, refer to the training course information at the end of this newsletter.

Corrections & Revisions to Canadian Standard Z94.4-02:During September 2003 I received my copy of the first update to the Canadian Standards Association guide on the Selection, Use, and Care of Respirators (Z94.4). The Update is dated April 2003 and replaces the original version dated October 2002. Several of the changes are corrections to errors. Only "registered" owners of Z94.4-02 received the changes, so if you have not registered your copy, do so now. For additional information, contact the Canadian Standards Association at 1-800-463-6727 or www.csa.ca

My last newsletter discussed a recent article that summarized fatal injuries involving respiratory protection. In response to that article a friend of mine told me of a respirator fatality in one of his former workplaces. While the fatality occurred many years ago, the story is worth sharing with my readers. In this workplace a supplied air system was installed to protect workers from the vapors of a common organic solvent. The system was connected to the plant's instrument air system. One day the system went down while the worker was using respiratory protection. Unfortunately, the system used nitrogen gas as a backup and the worker died of oxygen deficiency when nitrogen was automatically introduced into the breathing air line. While OSHA prohibits the introduction of any asphyxiating substance into breathing air lines, this was fairly common at one time. Today, many companies uses filtration panels connected to plant air. We should use this as a reminder to ensure these plant air systems do not have backups that can introduce an asphyxiating gas during a power outage or other circumstances. It wasn't too long ago the entire northeastern region of the US lost electrical power during the power outage of August 2003.

Most of us already know that OSHA permits the use of contact lenses with full facepiece respirators. In many, if not most cases, contact lens use is frequently preferred. The use of contact lenses in an industrial environment is, however, a more complex issue that is frequently confused by myth and urban legend. Recently the Eye and Vision committee of the American College of Occupational and Environmental Medicine published a guideline on the Use of Contact Lenses in an Industrial Environment. To review this guideline go to www.ACOEM.org and select Position Statements/Guidelines from the left hand column. Then select guidelines.

When long term storage of cylinders containing Grade D breathing air is needed, here are a few storage tips: Store the cylinders at reduced pressure in the vertical position (ie, valve up). Make sure the cylinders are not inverted. Vertical storage (ie, valve up) helps reduce corrosion by minimizing metal and water contact. Grade D air, while "dry", does have moisture in it. This is especially important for cylinders constructed of steel, which are more prone to corrosion. Remember, this suggestion refers specifically to "long term" storage. Another helpful hint is to slowly depressurize and discard the air from SCBA cylinders
that have not been used within a 12 month period of time. Doing this helps ensure the quality of breathing air that could degrade due to corrosion and oxidation. Don't store cylinders partially full. While we're on this topic, number or color code your air cylinders to facilitate your rotation schedule if they are not frequently used.

During respirator training classes I'm frequently asked if it is necessary to develop a cartridge change out schedule for voluntary use of chemical cartridge respirators. The answer is: absolutely, yes! Although the cartridge may be used in an atmosphere where individual solvent vapors are below respective exposure limits and respiratory protection is not required, it is possible that the one or more vapors with weaker adsorption affinity gets kicked off the cartridge by other vapors having a stronger affinity. As the cartridge reaches saturation it is possible for a worker to inhale a higher concentration of the vapor even though a respirator is being worn. The bottom line is a chemical cartridge change out schedule must be developed even when exposures do not require respiratory protection. To learn more about chemical cartridge change out schedules and respirator selection, consider taking our one day training class. For information about this class visit www.DrMcKay.com

NIOSH announced criteria on October 8, 2003, that it will use under an expedited program to test and certify escape respirators for emergency preparedness in the workplace. In the case of workplace preparedness for chemical, biological, radiological, and nuclear agents these escape respirators (also known as escape hoods), are designed to protect users from breathing harmful gases, vapors, fumes, and dusts for a limited amount of time needed to reach fresh air.

Escape respirators that pass the full set of tests will be approved by NIOSH, allowing manufacturers to label the approved products as NIOSH certified against chemical, biological, radiological, and nuclear (CBRN) agents in workplace escape emergencies.

These escape respirators will come in two types. One type, called a self contained escape respirator, consists of a hood with a tightly fitting neck piece and a contained source of breathing air. The hood provides a barrier against contaminated outside air, and the user breathes air from the attached source. In the other type, called an air purifying escape respirator, a filter canister is mounted on the hood. The user breathes outside air through the canister, which filters out harmful contaminants before the air is breathed.

NIOSH approvals will be based on positive results from rigorous tests on sample units voluntarily submitted to NIOSH by manufacturers, and from stringent evaluation of manufacturers' quality control practices, technical specifications, and other documentation. Both types of escape respirators will be tested against the chemical warfare agents Sarin and mustard. Air purifying escape respirators also will be tested against 10 chemicals and a particulate that will represent a wider range of 139 chemical gases and vapors, biological particulates, and radiological and nuclear dust particles. NIOSH developed the criteria with extensive advice and review by respirator manufacturers and other stakeholders, including other federal agencies, industry organizations, and labor representatives.

For further information about the certification program, visit the NIOSH web site at www.cdc.gov/niosh/npptl/default.html or call toll free 1-800-35-NIOSH.

OSHA is convening an informal public hearing in Washington DC on January 28, 2004 to receive testimony and documentary evidence on Assigned Protection Factors (APF's). If you wish to provide testimony at the public hearing you must notify OSHA in writing of your intention to do so no later than December 12, 2003. Details on this process can be found in the Federal Register: November 12, 2003 (Vol 68, number 218) or visit www.OSHA.gov

While smoking accounts for 16 million cases of chronic obstructive pulmonary disease (COPD), workplace exposures to dusts and irritants may account for as many as five million (5,000,000)! COPD kills more than 100,000 Americans each year. COPD is more frequent in people who have exposures to irritating materials in the workplace. While smoking prevention programs are important to reduce the incidence of COPD, controlling hazardous exposures could also play an important role. So remember to wear those respirators and be sure they fit well. Thanks to researchers at the University of California, San Francisco who reported this data.

NIOSH recently granted the first CBRN approval for a SCBA upgrade kit. Previously, NIOSH has approved several SCBA's for CBRN use, however, in this case the approval is for an upgrade kit. Specified models of previously deployed Scott Health & Safety self-contained breathing apparatus (SCBA) may now be upgraded for protection against chemical, biological, radiological, and nuclear (CBRN) agents using procedures and materials certified by NIOSH.

NIOSH announced the certification to Scott Health & Safety on September 11, 2003. The approved procedures and materials apply to upgrades of Scott Health & Safety's Model 4.5 Air-Pak 30-minute, 45-minute, and 60-minute open-circuit, pressure-demand, self-contained breathing apparatus. The ability to upgrade previously purchased and deployed SCBA using this approval would provide an alternate method for emergency responders to achieve CBRN protection without purchasing new SCBA respirators.

This approval signifies that the products receiving the upgrade are expected to protect firefighters and other emergency responders from CBRN related gaseous, airborne particulate, and liquid respiratory exposures. This approval action allows a qualified Scott Health & Safety technical representative to inspect, modify, and test previously deployed 4.5 models by following approved procedures to achieve CBRN protection, and to apply a label designating the respirator as having received a CBRN retrofit.

NIOSH approval does not constitute a commercial endorsement of these or any products. Appearance in this newsletter is not a commercial endorsement. Rather, the appearance in this newsletter is provided as a mechanism to share information and help educate others on the NIOSH process. At various times other manufacturers equipment have been featured. As a reminder all certifications are posted on the NIOSH web page at www.cdc.gov/niosh/npptl/cbrncheck.html

For additional information on NIOSH's program for testing and certifying respirators for use by responders against chemical, biological, radiological, and nuclear exposures, call the toll-free NIOSH number, 1-800-35-NIOSH (1-800-356-4674) or visit the web page for NIOSH's National Personal Protective Technology Laboratory at www.cdc.gov/niosh/npptl/default.html

ANSI recently approved the updated Z87.1-2003 standard. With respect to respirators the updated standard addresses NIOSH approved loose and tight fitting facepieces for protection from impact hazards and eye irritants. Optical radiation is also addressed for welding respirators. For more information visit www.asse.org.

Congratulations to Erin Snyder, a former graduate student working in Dr. McKay's fit testing laboratory and now a NIOSH employee. Erin published the following article in Applied Occupational and Environmental Hygiene, Volume 18, 702-707, 2003: An Evaluation of Irritant Smoke to Detect Exhalation Valve Leakage in Respirators. These studies showed that irritant smoke fit testing procedures were unable to adequately detect fit factors less than 100 in respirators having exhalation valve leakage. Authors of the study were Erin and Dr. McKay. Studies were conducted at the University of Cincinnati.

Roy McKay, Ph.D.
Course Director
University of Cincinnati
www.DrMcKay.com