Wednesday, October 6, 2010

New Book on AEGLs Published by the National Academies Press

The National Academies Press published a book recently discussing the Environmental Protection Agency’s (EPA’s) Acute Exposure Guideline Levels (AEGLs) for Selected Airborne Chemicals. The book provides comprehensive summaries of studies and experiments that the EPA used when determining exposure limits for certain chemicals.

One chemical discussed in the book is Peracetic Acid (PAA), which we have discussed in detail on this blog before. PAA has been receiving increased attention in recent years, as its use as a disinfectant against bacteria, fungi, and viruses is becoming more widespread in both the healthcare and food industries. PAA can be quite harmful in the event of exposure as it is corrosive and irritating to the eyes, mucous membranes of the respiratory tract, and skin. As the chapter states, “extreme discomfort and irritation” can occur in humans after exposure to just 5ppm for 3 minutes. Lethal concentrations of PAA can cause hemorrhage, edema, and consolidation of the lungs of those exposed.

The EPA typically sets 3 different AEGL values for chemicals. In general, the first level refers to the concentration of a chemical which would cause discomfort, the second long lasting adverse health effects, and the third life-threatening health effects. AEGL 1 for PAA is set at 0.17ppm, which is considered to be the threshold for irritation to mucous membranes and eyes. AEGL 2 is set at 0.5ppm, the concentration at which “slight to tolerable discomfort to nasal membranes and eyes” begins to occur. AEGL 3 is set at 4.1mg/m3 (which is not converted to ppm because values are based on exposure to aerosol). While the data for AEGL 3 was based on studies in animals (rats and mice), there is evidence that humans may be slightly more sensitive to PAA.

As we have pointed out before, there is currently no OSHA Permissible Exposure Limit (PEL) for PAA. With the recent actions taken by the administration, there is reason to believe that a new round of PELs may be issued in the near future. However, it is important to remember that OSHA PELs are not an all inclusive list of chemicals that could be harmful to humans if exposed. Data reported by the EPA in articles and books like this serve as practical reminders that chemicals used to protect us can also hurt us if we don’t protect ourselves from potential exposure.

A link to a free PDF download of the new book about AEGLs can be found here:

No comments:

Post a Comment