Written By: Robert E. Sheriff, MS, CIH, CSP, President
September 30, 2019
Glutaraldehyde and Formaldehyde
Glutaraldehyde is very similar to formaldehyde in its structure and uses in the healthcare industry. Chemically, Glutaraldehyde exists at room temperature as a liquid, whereas formaldehyde exists under those conditions as a gas, which can easily be dissolved in water.
Glutaraldehyde is often used as a substitute for formaldehyde because formaldehyde is now a suspect cancer-causing substance. Glutaraldehyde may be a good substitute for formaldehyde/formalin but it appears to be more irritating than formalin. Eye, throat and lung irritation has often been traced to glutaraldehyde. Some medical schools have introduced glutaraldehyde in cadavers for student laboratories but the results have been mixed both as a tissue preservative and as an irritant. Asthma and asthma-like symptoms have been identified by NIOSH in their investigation of hospital occurrences of the symptoms just mentioned (“Glutaraldehyde – Occupational Hazards in Hospitals”). Contact dermatitis, hives, staining of hands (tan) and nausea are other symptoms of glutaraldehyde exposure identified by NIOSH.
Formaldehyde is used as a disinfectant, as well as a tissue preservative. As a tissue preservative, it can be found in histology labs where tissues are sectioned and prepared for microscopic analysis. Of course, autopsies can also subject the examiner and assisting personnel in formaldehyde vapors.
Healthcare workers use formaldehyde containing solutions as a disinfectant as well. Of course, such professionals as dentists and veterinarians will also find formaldehyde in their cleaning/disinfecting and preserving solutions.
An Often Used Chemical
Glutaraldehyde has many uses as a disinfectant and a tissue preservative in hospitals, labs, pharmacies, outpatient treatment centers, and of course, morgues. It has found steady use for cold sterilization where equipment may be heat sensitive such as surgical instruments that are not totally metallic, dialysis equipment, bronchoscopes, ear, nose and throat instruments, and suction bottles. Further, it is used as a tissue fixative for histology and pathology and in some instances, as a cadaver preservative in morgues as a substitute for formaldehyde (actually formalin which is a combination of formaldehyde and alcohols).
Persons in hospitals and other medical-related fields who may be exposed to glutaraldehyde include:
- Medical Students and Teachers
- Cold Sterilization Staff
- Operating Room Personnel
- Dialysis Personnel
- Intensive Care-Infection Control Staff
- Histology Lab Technicians
- Medical Researchers
- Central Service and Maintenance
- Workers Who Develop X-Rays
- Mixing and Diluting Sterilization Solutions
Did you know that medical students are very likely overexposed to formaldehyde in anatomy laboratories? Cadavers studied by medical students are preserved in formalin, a combination of formaldehyde and alcohol. Air testing/sampling of medical students and staff in many medical schools show regular exceedances of the OSHA Permissible Exposure Limit (PEL)—and certainly well above a recommended safe level considering it is a cancer causing substance. The controversy is that medical students are not employees and thus not under OSHA jurisdiction. But the medical staff is covered by OSHA!
OSHA’s PEL for formaldehyde (0.75 ppm – 8-hour time-weighted average) does not reflect a level that considers its carcinogenicity. Due to legal challenges, OSHA has not been successful in reducing the PEL to where it would be considered a reasonably safe level in a working environment, such as a hospital or laboratory.
A number of agencies throughout the country—and the world—have established much lower levels than OSHA with the carcinogenicity factor in mind. Health Canada recommends a 30 minute limit of 0.1 ppm. The World Health Organization (WHO) recommends a 30-minute limit of 0.08 ppm for the general public, and NIOSH recommends an occupational (worker) exposure limit of 0.016 ppm (8-hour time-weighted average).
It is relatively easy to monitor medical staff personnel and hospital departments for glutaraldehyde. It gets much more complicated in correcting exposure problems, especially where substitute solutions are not as effective in dealing with sterilization needs. Corrective measures and exposure controls may require the services of a specialist such as an industrial hygienist. Controls such as downdraft tables, lab hoods, local exhaust ventilation, and respiratory protection must be considered as options.
Formaldehyde can be fairly and easily sampled in the air. A variety of testing methods can be employed to evaluate hospitals and healthcare workers. The interpretation of the results and defining workable protection and exposure reductions is another matter. An industrial hygienist may be the most suitable person to do the testing, evaluate and recommend corrective measures when it comes to formaldehyde health and safety.
Control measures are highly dependent upon use and exposure concentrations but can include downdraft ventilation, hoods, local exhaust, skin and body protection, and respiratory protection.
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