November 14, 2019

Researchers Examine Exposures from Use of Biological Degreasing Stations

A recent study published by IRSST, a nonprofit scientific research organization in Québec, Canada, examined workers’ exposure to microorganisms when using biological degreasing stations. These stations use a degreasing agent containing bacteria that break down fats, oils, and greases by mineralization. According to IRSST, manufacturers of the agents used in biological degreasing stations claim that the microorganisms they contain are harmless because they are classified as Risk Group 1 under the four-group infection risk ranking system used in most countries. The Public Health Agency of Canada describes Risk Group 1 microorganisms as posing a low risk to the health of individuals and to public health. However, previous research identified a number of Risk Group 2 bacteria such as Pseudomonas aeruginosa and Klebsiella pneumoniae in biological degreasing station solutions. Risk Group 2 bacteria represent moderate risk to the health of individuals and low risk to the community. The purpose of IRSST’s recent study was to assess occupational risk of exposure to these microorganisms through inhalation.

IRSST researchers who monitored the fluids in five biological degreasing stations over one year identified 60 bacterial species from both Risk Group 1 and Risk Group 2. The study found that the biological degreasing stations were rapidly colonized by exogenous microorganisms such as Pseudomonas aeruginosa and that the main risk with skin contact is wound infection or accidental ingestion. According to the authors, strict personal hygiene measures—wearing gloves and handwashing, for example—are necessary before and after using biological degreasing stations. The results also showed that workers using these stations have very low exposure to bioaerosols.

“While recommended intervention levels for occupational exposure to bioaerosols are around 104 CFU/m³, the average ambient concentrations measured during this study were all below 480 CFU/m³,” IRSST’s report explains. “Moreover, use of an air blower to dry parts degreased in the biological degreasing stations did not significantly increase worker exposure to culturable microorganisms.”

Based on these findings, the authors of the study do not recommend respiratory protection during biological degreasing station use.

IRSST’s full report is available online.