NIOSH: How safe is peracetic acid for healthcare workers?
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September 7, 2017
The substance is an increasingly common ingredient in high-level disinfectants, but there’s still a lot we don’t know about its health effects for workers.
Prior to the 2000s, glutaraldehyde was the preferred high-level disinfectant (HLD) in healthcare settings. The chemical was estimated to account for 84% to 89% of applications. Its dominance has been softening, however, in recent decades as an increasing number of organizations have turned to other active ingredients, including peracetic acid, to sterilize equipment and facilities, according to the results of a 2011 survey published three years later in Infection Control & Hospital Epidemiology.
The survey, which asked more than 4,600 healthcare workers about the chemicals they use, determined that glutaraldehyde remains the most popular (59% of HLDs), followed by peracetic acid (16%), then ortho-phthalaldehyde (15%). While these substances are used in similar applications, there are differences in the ways they are regulated—and that can impact perceptions of their relative safety.
Several factors could be driving the rising popularity of alternatives to glutaraldehyde, says study coauthor James M. Boiano, MS, CIH, a senior industrial hygienist and assistant coordinator of the NIOSH Healthcare and Social Assistance Sector Program. Notably, there is an enforceable occupational exposure limit for glutaraldehyde but not for peracetic acid. That can lead users to believe the alternatives are safer or otherwise less toxic, Boiano says.
“It should be noted, however, that [ortho-phthalaldehyde] has been shown to cause similar health effects as glutaraldehyde,” he says.
Switching to one of the alternatives could also be attractive for other reasons: to reduce disinfection time, lessen the risk of exposure by inhalation (due to lower vapor pressure), or accommodate other needs specific to the user, Boiano adds.
When healthcare workers fail to appreciate the hazards posed by a given chemical, they run the risk of making matters worse by failing to protect themselves. The same survey that found rising use of peracetic acid also found significant rates of potentially dangerous handling practices: 5% of respondents reported having experienced an HLD spill or leak, 9% failed to wear gloves, 17% lacked training in safe handling, 19% lacked standard procedures to minimize exposure, and 44% failed to wear water-resistant gowns.
“This survey indicates that the use of recommended PPE, particularly gowns/outer garments, is not universal among workers who use HLDs to disinfect medical instruments,” Boiano and his coauthors wrote in their survey report. “Best practices for handling HLDs, including wearing protective gloves, water-resistant gowns, and eye/face protection to minimize skin and eye exposure, are not always followed. The most commonly reported reason for the underutilization of gloves, gowns, and eye/face protection suggests a perception that exposures are negligible or so infrequent that they do not warrant their use. Lack of training on safe handling practices and lack of employer standard procedures suggest that employers may not fully recognize the hazards and potential adverse health effects of HLDs.”
Currently, NIOSH has neither a recommended exposure limit nor an immediately dangerous to life or health (IDLH) value for peracetic acid. Similarly, OSHA has no permissible exposure limit for the substance. But that could change. In 2015, NIOSH had proposed establishing an IDLH value for peracetic acid at 1.7 mg/m3, but public feedback persuaded the agency to put those plans on hold.
“The public comments indicated that (1) the proposed IDLH value was overprotective, (2) the data available for peracetic acid are of low quality, and (3) issues exist with sampling and analysis of air samples for peracetic acid in the workplace,” the agency explained earlier this year in a request for information. “Based on these comments, NIOSH is reevaluating the proposed IDLH value for peracetic acid.”
Now NIOSH is seeking public comments to inform the agency’s evaluation, including epidemiological and field studies, quantitative risk assessments, evaluations of workplace controls, and other information. Among those who have responded thus far is Rick Huston, senior director of plant operations and safety officer for HealthPartners Regions Hospital in St. Paul, Minnesota.
“Regions Hospital considered using peracetic acid as part of our general routine cleaning of two patient care areas which encompassed patient rooms,” Huston wrote in a comment. “These rooms included patient rooms, restrooms, utility rooms, work spaces, and all other ancillary spaces within the patient care units.”
The hospital had already used peracetic acid in its sterile processing department for certain applications, such as surgical equipment. Then, last year, the hospital conducted a trial on a peracetic acid product. About 10 employees were exposed to the chemical.
“Some staff reported irritated respiratory systems, but others felt no effects from working with the chemicals. We decided not to move forward with the chemical for housekeeping cleaning purposes due to employee and patient safety concerns,” Huston wrote.
“In our findings,” he added, “the level of staff training and education, concentration of the cleaning agent, and the environment of care are all factors worth studying when determining the applicability of using peracetic acid.”
The stated end goal of NIOSH’s current comment-collection process is to develop “appropriate communication products that convey the potential health risks, recommended measures for safe handling, and establish exposure recommendations.” Comments had been due in June, but the collection period was extended four months to October 1, 2017. To review the latest comments or submit your own, view the online docket.
For the time being
While the powers that be continue to consider how best to communicate hazards associated with peracetic acid (and other HLDs, for that matter), employers should continue referring to safety data sheets (SDS) for guidance, Boiano says. The OSHA Hazard Communication standard requires that these sheets be available in the workplace to ensure that workers have access to information on the hazards each chemical poses and the proper techniques for handling, storage, and transportation. Study this information carefully, then proceed with caution.
“The health effects of peracetic acid (PAA) exposure include irritation of the skin, eyes, and mucous membranes of the nose and throat following acute exposure via direct contact or inhalation, and bronchitis and chemical pneumonitis following repeated or prolonged inhalation exposure,” Boiano says. “Because the long-term health effects of exposure (e.g., cancer, adverse reproductive outcomes) are unknown, prudence dictates that a precautionary approach be taken to minimize the likelihood of exposure.”
Employers should also cut their chances of exposure through the use of solid industrial practices, Boiano adds.
“This would include implementing the hierarchy of controls in the following decreasing order of efficacy: substitution, engineering controls, following administrative controls, work practice controls, and personal protective equipment,” he says. “Should workers experience symptoms related to exposure to PAA, they should notify their employer’s health and safety department, occupational health unit, or their doctor so that the work environment is evaluated and corrective actions can be taken.”
Peracetic acid facts
What is it? Peracetic acid is a peroxide-based molecule used extensively as an antimicrobial agent in many commercial applications.
When is it used? It is routinely used as a sterilant during the cleaning of endoscopes and other medical devices, as a disinfectant in food processing, as a bleaching agent, and in the synthesis of other chemicals.
How is it diluted? Technical and commercial peracetic acid products contain peracetic acid, acetic acid, and hydrogen peroxide in solution. Concentrations of peracetic acid in these products vary but do not exceed 40%.
How might it affect workers? Acute exposure to peracetic acid is irritating to the eyes, respiratory tract, and skin. Peracetic acid is a strong sensory irritant considered to be more potent than acetic acid or hydrogen peroxide.
(This information was adapted from a document published by the CDC: www.regulations.gov/document?D=CDC-2017-0015-0001.)