It’s not just latex that may be causing occupational asthma
February 1, 2001 8 minutes read
It’s not just latex that may be causing occupational asthma
OSHA to develop glutaraldehyde exposure limit
Uncontrolled exposures to the disinfectant glutaraldehyde may be widespread in hospitals around the country, contributing to a prevalence of occupational asthma among nonsmokers that is estimated to be higher than in any other industry.
The impact of occupational asthma ranges from mild sensitivity to death. Of the 10 occupations with the highest proportionate mortality from asthma, five of them are in health care, according to surveillance data collected by the National Institute on Occupational Safety and Health (NIOSH).1 While latex allergy is the most likely cause of severe asthma incidents in hospitals, glutaraldehyde plays a role in broad and underreported episodes of respiratory sensitization, occupational asthma experts say.
"Five percent to 10% of health care workers have some exposure to glutaraldehyde," says Edward Lee Petsonk, MD, senior medical officer in the division of respiratory disease studies at NIOSH in Morgantown, WV. "We’re talking about hundreds of thousands of potentially exposed individuals."
The Occupational Safety and Health Administration (OSHA) is developing a permissible exposure limit (PEL) that is likely to be four times lower than the 0.2 ppm that was included in an air contaminants standard in 1989. The standard has been voided by a federal court, leaving no current enforceable limit.
Yet even if hospitals conduct routine monitoring and provide controls of central processing units, they may not be adequately protecting workers. Glutaraldehyde often is used in various types of containers throughout a hospital and its satellite clinics, typically poured down the sink, or even sprayed on surfaces as a contact cleaner, a practice that is considered particularly troubling.
"The institutionalized practice of how glutaraldehyde is used in many hospitals, big and small, is completely erratic," says Jamie Tessler, MPH, research associate with the Sustainable Hospitals Project, a program on pollution prevention and occupational health at the University of Massachusetts in Lowell. "There is no uniform across-the-board standardized method of controlling exposure to glutaraldehyde. Common practice at many locations within a facility is what I call a dinosaur — an open bin of glutaraldehyde to which workers, and potentially patients, are exposed, and the risk of spills is great."
Employee health professionals and safety officers may not be fully aware of the hazards of glutaraldehyde without some investigation, Tessler notes. After all, the symptoms of burning eyes or a headache usually go away when the exposure stops. Employees who begin to have respiratory problems typically go to a primary care physician and may not make the connection with work exposures.
"Physicians often don’t make a connection between their patients’ asthma and their jobs," says Catharine Tumpowsky, MPH, director of the work-related asthma surveillance project in Massachusetts, one of four states reporting occupational asthma data to NIOSH. "We suspect that there is tremendous underreporting of work-related asthma in the state."
Meanwhile, glutaraldehyde may be used in a multitude of settings to disinfect equipment, such as endoscopes or gynecologic speculum, and to fix film in radiology department darkrooms. When safety professionals at one 600-bed hospital conducted a thorough survey of uses of glutaraldehyde, they found more than 30 uncontrolled sites, including uncovered bins or plastic containers.2
Without an OSHA regulation, efforts used to reduce exposure depend on the safety consciousness of the department manager, Tessler says. "In one clinical area, you might have state-of-the-art technology, [while] in another area, you might have uncovered bins," she says. "Each department has independent strategies depending on who’s directing the use of it." In some cases, an open bin might rest on a cart in a patient room, potentially exposing patients to vapors. Industrial hygienists also have found glutaraldehyde used when high-level disinfection wasn’t even necessary.
Monitoring uses a 15-minute, time-weighted average to measure the exposure. So while experts say the .05 ppm is a level that should never be exceeded, current monitoring techniques would miss a momentary "peak," notes Tessler.
An unpublished survey of New Jersey hospitals found that slightly more than half (55%) were conducting air monitoring for glutaraldehyde. Of those, 36% had recorded levels that exceed limits recommended by the American Conference of Governmental Industrial Hygienists in Cincinnati. Independent air sampling conducted by the state’s Occupational Health Surveillance Program found just 11% of 54 samples taken at 10 hospitals registered levels exceeding the .05 ppm limit.
Activating and mixing new glutaraldehyde solution posed the greatest risk of exposure in the sampling, says Donald P. Schill, MS, CIH, project coordinator of the program, which is part of the New Jersey Department of Health and Senior Services in Trenton. That involves mixing a buffering agent into a gallon jug of glutaraldehyde.
However, Schill noted that certain activities weren’t captured by the sampling, such as pouring glutaraldehyde down a sink drain (with the water running to dilute it) and the use of open containers in areas other than the operating room, which has frequent air exchange. Exposures during spills also could greatly exceed recommended levels. "We are very suspicious that spills contribute a lot to people developing symptoms," says Schill, an industrial hygienist. "A single high acute exposure can trigger the sensitization. Then lower exposures thereafter could cause symptoms. That is true of irritants in general."
OSHA tried to establish exposure limits to glutaraldehyde as part of a 1989 air contaminants standard. However, in 1992, the 11th Circuit Court ruled that OSHA hadn’t met its regulatory burden of showing substantial risk of harm from the current exposure limits to a large number of chemicals. The court voided the standard and sent it back to OSHA for further work. In the case of glutaraldehyde, that meant the 0.2 ppm standard never became effective, and OSHA currently has no regulation requiring monitoring and maximum levels for the disinfectant.
In its aborted standard, OSHA cited studies showing "significant risk of irritation to the eyes, nose, and throat associated with short-term exposures to glutaraldehyde at concentrations of 0.3 ppm or above." The agency concluded, "OSHA considers the irritation effects associated with exposure to glutaraldehyde to be material impairments of health."3 In fact, subsequent studies showed that glutaraldehyde causes respiratory sensitization at even lower levels than the irritant effects.
During the next 12 years after OSHA’s attempts to regulate indoor air quality, little research occurred in the United States on glutaraldehyde’s effects in a health care setting. But research in Britain, Italy, and other European countries showed a link between the substance and occupational asthma at hospitals. In one study of 24 health care workers with asthmatic symptoms, a diagnosis of occupational asthma was confirmed in all but three. In seven cases, researchers measured an immunologic response to glutaraldehyde.4
Their symptoms improved when not at work
All the workers experienced respiratory symptoms, such as cough and chest tightness, when exposed to glutaraldehyde but an improvement of symptoms when they were off from work. Occupational asthma evolved over an average of 6.7 years, and 42% first had more minor nasal symptoms, such as stuffiness and sneezing. Such evidence led health officials in the United Kingdom to withdraw its 0.2 ppm maximum exposure limit and issue an alert. "Because of the information now available on the health effects of glutaraldehyde, the [occupational health expert] committee could no longer identify a level which is both safe and practicably achievable," the alert stated.
The Health and Safety Commission moved toward a maximum exposure limit (MEL) of .05 ppm, which places a "duty on the employer to reduce exposure to as low as is reasonably practicable, and in any case below the MEL."
The American Conference of Governmental Industrial Hygienists reviewed the medical literature and the actions of other countries in 1997 and lowered its ceiling threshold limit value to .05 ppm, noting that it is an "airborne concentration that should not be exceeded during any part of the work shift."5
NIOSH is reviewing medical literature and is expected to set a lower recommended exposure limit by 2002. "Effects appear to be occurring below [the current REL of 0.2 ppm]," says Joann Wess, MS, a biologist in the education and information division of NIOSH in Cincinnati. NIOSH also is publishing a brochure on glutaraldehyde geared toward workers, she says.
As evidence accumulates and other organizations set lower exposure limits, OSHA’s review of glutaraldehyde gains steam. Surveillance data collected by NIOSH provide further impetus. For example, in Massachusetts, 12% of health care workers with occupational asthma who were interviewed by health officials said they were exposed to glutaraldehyde.
"In taking a look at the chemicals . . . [whose permissible exposure limits were] vacated by the 11th circuit, we collected some information on the degree of the hazard and how many workers are exposed," says Lyn Penniman, RN, MPH, health scientist with OSHA’s directorate of health standards program. "We identified some chemicals we were going to take a closer look at, and glutaraldehyde was one of those."
Scientific evidence linking glutaraldehyde to respiratory effects and asthma is critical, says Penniman. "When OSHA does come out with a proposed standard, what you will see is a proposed PEL based on a quantitative risk assessment. That’s what the court said we need to do, and that’s been the holdup all this time."
Even in the absence of a standard, employers are expected to control hazards under OSHA’s "general duty" clause. "This is a recognized hazard," says Penniman. "Employers are required to maintain a workplace that’s free of recognized hazards."
Even mild symptoms should be cause for concern, occupational health experts say, because they may be a precursor of more serious effects. In the New Jersey survey, three-quarters of respondents reported smelling the odor of glutaraldehyde, which means they had some level of exposure. The most common symptoms were burning eyes, nasal stuffiness, and headache.
Employee health professionals should use a questionnaire to determine if workers using glutaraldehyde are experiencing any symptoms, Petsonk advises. Even a single case of occupational asthma linked to glutaraldehyde can be a "sentinel event," he says. "If someone develops asthma in response to glutaraldehyde, that should raise concerns that others may be [having the same problem]," he points out.
As with many other conditions, early detection is critical. "People who get work-related asthma can improve and even have their condition resolved completely if they control their exposure adequately and early," says Petsonk. "If they continue to be exposed and don’t control the exposure early . . . it can become a lifelong problem."
[Editor’s note: Work-Related Lung Disease Surveillance Report 1999 is available on the NIOSH Web site at www.cdc.gov/niosh/w99cont.html or from the Surveillance Branch of the Division of Respiratory Disease Studies, NIOSH, 1095 Willowdale Road, Morgantown, WV 26505-2888. Fact sheets and information on glutaraldehyde controls and alternatives are available on the Web sites of the Sustainable Hospitals Project at the University of Massachusetts in Lowell (www.sustainablehospitals.org) and the Occupational Health Surveillance Program of the New Jersey Department of Health and Senior Services (www.state.nj.us/health/eoh).]
References
1. National Institute for Occupational Safety and Health. Work-Related Lung Disease Surveillance Report. DHHS (NIOSH) No. 2000-105. Morgantown, WV; 1999.
2. Tessler J. Strategies to reduce or eliminate glutaraldehyde from hospitals. Presented at the 128th Annual Meeting of the American Public Health Association. Boston; November 2000.
3. Occupational Safety and Health Administration. Air Contaminants (29 CFR 1910.1000). Washington, DC; 1989.
4. Di Stefano F, Siriruttanapruk S, McCoach J, Sherwood Burge P. Glutaraldehyde: an occupational hazard in the hospital setting. Allergy 1999; 54:1,105-1,109.
5. American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices, 6th ed. Publication 0206, Cincinnati; 1999.
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