Insights for Managing Enzyme Exposures
By Kay Bechtold
On Tuesday morning at AIHA Connect 2025, two consultants highlighted the importance of protecting workers from exposures to enzymes, which are proteins that can help speed chemical reactions or break down organic materials. According to BSI’s Naeole Nathaniel, CIH, CSP, and Miriam Koesterich, MS, CIH, CSP, enzymes are used in a variety of industries—for example, in pharmaceuticals as diagnostic reagents and in the manufacture of products like paper, textiles, and detergents. A common enzyme used in laundry detergent manufacturing is subtilisin, a protease enzyme that breaks down proteins, a property Koesterich said is helpful in removing stains from grass and body fluids. Though enzymes are widely used in industry, they can cause serious health effects among exposed workers, including allergic reactions and occupational asthma. Koesterich, whose main client is a laundry detergent manufacturer, emphasized that while many enzymes are respiratory irritants, “even more are sensitizers.”
Enzymes are found in liquid, powder, and granule forms. In granule form, powder is encapsulated with an alginate-derived material made from seaweed, Koesterich said. While encapsulation can reduce exposures to enzymes, it does not eliminate them, as she illustrated using two examples of historical cases. When enzymes were introduced into detergent manufacturing in the 1960s, a pattern of occupational asthma emerged, Koesterich said. This pattern led to the use of encapsulation, which helped lower workers’ exposure to enzymes in the detergent dust. But an outbreak of asthma that occurred approximately 40 years later, in the 2000s, demonstrated that the risk was still present. The 2000s asthma outbreak took place at a facility that used only encapsulated detergent, showing that encapsulated particles could become unencapsulated due to friction, abrasion, and other damage, exposing workers to enzymes.
OSHA does not have a permissible exposure limit or action level for enzymes, Nathaniel said, so occupational and environmental health and safety professionals typically follow the ACGIH Threshold Limit Value–Ceiling of 60 ng/m3. While this ceiling limit is specific to subtilisin, the most common protease enzyme, Nathaniel explained that it’s been widely used as a standard exposure limit for other enzymes. This value matches NIOSH’s short-term exposure limit for subtilisin, but Nathaniel pointed out that the agency recommends lowering the limit to 6–15 ng/m3 in cases where the enzyme is combined with surfactants. Industry best practice is to use general dust as a surrogate for exposure, Nathaniel said—that is, if general dust levels are kept below a certain limit, the enzyme exposure should also be within those limits.
Exposures to enzymes usually occur at employee workstations, in areas where workers are hand scooping or mixing, and in places where enzymes are stored. Nathaniel noted several considerations for industrial hygienists and OEHS professionals when it comes to enzyme sampling. For example, the “main concern with the type of filter that you’re using [for the cassettes] is that it needs to not have any protein-binding characteristics,” he said. Nathaniel also encouraged attendees to make note of the pore size on the filters; for high-volume sampling of an area, it’s necessary to ensure that the pore size will accommodate a high flow rate. Personal sampling can be done with “any standard pump you’d use for industrial hygiene sampling,” Nathaniel added. As no regulatory levels exist for surface exposure to enzymes, Nathaniel and his team have used surface sampling of high-touch points to “check if containment protocols are being followed and if there’s any risk of enzymes getting out where they shouldn’t be”—for example, in breakrooms, restrooms, and outside of enclosures. In the absence of guidelines, Nathaniel encouraged IHs to be consistent with surface sampling for enzymes to ensure that results can be compared.
Nathaniel and Koesterich recommended that IHs “work hand in hand” with laboratories to ensure that they’re getting proper analysis of samples. A few recommendations they shared included using a new or clean, dry glass or plastic container; storing samples refrigerated or frozen; and shipping samples at the fastest rate possible. Since enzymes are biologically active materials, they can degrade over time if not stored properly, Nathaniel cautioned.
As with other hazards, a variety of control methods are available to help protect workers from exposure to enzymes. Nathaniel described encapsulation as the “best control” and the one used most but stressed that the “key is to reduce abrasion to granules.” As science and products improve over time, workplaces should be able to use higher quality encapsulation. But because encapsulation can be damaged, the presenters encouraged attendees to use many different controls to help minimize exposures.
A possible engineering control is the containment of processes involving enzymes. If containment or enclosure is not possible, the presenters noted that local exhaust ventilation can be effective. Administrative controls that can help address exposures to enzymes include rotating workers’ shifts to reduce exposure duration, ensuring that housekeeping protocols are being followed, cleaning spills promptly and properly, and conducting medical surveillance to help identify any allergies early on. Nathaniel described respiratory protection for “typical” exposure to enzymes as an N95, though higher exposures may warrant a powered air-purifying respirator with a particulate filter.
Kay Bechtold is managing editor of The Synergist.