Comparison between OSHA PELs and EH40 Occupational Exposure Limits

Here in the US we are used to thinking about OSHA and permissible exposure limits (PELs), but every industrialized country has their own occupational exposure limits. Many countries or provinces either base their exposure limits on the ACGIH TLVs or reference them exactly.

The European Union has developed its own set of occupational exposure levels which are implemented in each EU country. The UK workplace exposure levels (WELs) are summarized in a document called EH40. The EH40 document is regularly updated and the last version was published in 2011 and is available from the UK’s Health and Safety Executive (analogous to OSHA) for £15 paper copy or free download. The EH40 also has a lot of useful information, such as how exposure limits are calculated etc.

It is interesting to make a comparison between the EH40 exposure values and the OSHA PELs in 29 CFR 1910.1000 and other OSHA standards for a few select compounds relevant to disinfection and sterilization in food and healthcare. In general the exposure limits are similar, which is to be expected since published research reports relevant to the effect of chemical occupational exposure is available world wide and neither standard is developed in a regulatory vacuum.

Ethylene oxide:
OSHA 1 ppm 8hr TWA, 5 ppm 15 min TWA
EH40 5 ppm 8 Hr TWA

Formaldehyde:
OSHA 0.75 ppm 8 Hr TWA, 2 ppm 15 min TWA
EH40 2 ppm 8 Hr TWA, 2 PPM 15 min TWA

Glutaraldehyde:
OSHA n/a
EH40 0.05 ppm 8 Hr TWA, 0.05 ppm 15 min TWA

Hydrogen Peroxide:
OSHA 1 ppm 8 Hr TWA
EH40 1 ppm 8 Hr TWA, 2 ppm 15 min TWA

Ozone:
OSHA 0.1 ppm 8 hr TWA
EH40 0.2 ppm 15 min TWA

This limited comparison shows that the OSHA standard is more stringent for ethylene oxide and formaldehyde (both fairly recent standards). Glutaraldehyde is not listed by OSHA, though OSHA recognizes the harmful effects of glutaraldehyde and provides guidance for its safe use. Unlike the EH40 values which are periodically updated, the OSHA PEL s are still largely the same as they were when first promulgated in 1972. OSHA is aware of the senior status of its PELs and is planning to update them.

One notable difference of note is the short term exposure limit (STEL) for hydrogen peroxide in the EH40. Hydrogen peroxide is widely used in healthcare and food processing for sterilization and disinfection and the STEL emphasizes the importance of avoiding even short term exposure to low ppm concentrations of hydrogen peroxide vapor.

While the EH40 WELs have no legal standing in the US, they can be used to provide an industry standard for what constitutes an safe level, in similar manner to other industry standards such as the ACGIH’s threshold limit values (TLVs); and are particularly useful for those compounds for which there are no OSHA PELs or for which the OSHA PELs are particularly obsolete.

However, several new compounds finding use in healthcare and the food industry such as peracetic acid and o-phthalaldehyde are listed in neither the OSHA PELs nor the EH40. While the EH40 is updated more regularly than the OSHA PELs, as with any government action, the regulatory wheels move slowly. Users should therefore consult other reliable sources to find appropriate safety information. The ACGIH had led the development of occupational exposure standards for over five decades and continues to lead today for example with its proposed STEL for PAA of 0.2 ppm (15 min TWA).

OSHA’s Regulatory Agenda

Towards the end of 2011, OSHA published its regulatory agenda for the upcoming year. Two items are especially relevant to gas detection in healthcare, food processing and other industries: The revision of the HazCom standard and the revision of the OSHA Permissible exposure limits (PELs).

HazCom
The Hazard Communication standard applies to all companies using chemicals and requires appropriate material safety data sheets (MSDSs), labels, employee training etc. One problem facing the HazCom Standard is that different government agencies apply different standards and across the world the standards differ significantly from country to country, meaning that different labels and MSDSs are needed from one location to the next. The United Nations has developed a global harmonization standard (GHS) that can be used to classify chemicals according to their properties. OSHA is working towards updating the HazCom standard to be compliant with the GHS.

OSHA PELs
Most of the current OSHA PELs were adopted under the 1970 Occupational Safety and Health Act (OSH Act) from the 1968 ACGIH TLV values, since they were already federally recognized consensus standards. With a few exceptions, the majority of the PELs today are unchanged since they were first adopted even though a considerable amount of chemical safety data has been collected since then and the ACGIH TLVs have been regularly updated. In 1989 OSHA attempted a broad updating of the PELs, introducing 164 new PELs and lowering 212 existing ones. However, these changes were subsequently overturned by the Eleventh Circuit Court of Appeals in 1992, on the grounds that OSHA failed to show the health benefits versus the cost of implementation for each individual compound, as required under the OSH Act. The PELs thus reverted back to their prior values. OSHA is again looking at revising the PELs, but the legal framework remains to be seen.

The ChemDAQ blog will be following both of these themes over time and will provide updates as more information becomes available.

Peracetic Acid Occupational Exposure Levels

Peracetic acid (PAA) is gaining wide acceptance as a disinfectant and sterilant in many industries including healthcare, food processing (aseptic packaging, bottling, dairy and meat) and water treatment. PAA acid is a relatively simple chemical formed as an equilibrium component in a mixture of hydrogen peroxide and acetic acid; with excellent disinfection properties and additionally PAA is environmentally benign since it rapidly breaks down to harmless product (acetic acid and water).

Any broad spectrum disinfectant or sterilant is potentially hazardous to people exposed to it and the widespread use of PAA has meant that there is the potential for workplace exposure. While employers have a duty to ensure a safe workplace [OSH Act (1970) sec. 5], it has been difficult to determine what level of PAA exposure is safe since there is no OSHA permissible exposure limit for PAA and little other guidance.

Guidance is now available: The EPA published acute exposure guidelines for PAA in 2010, available at http://www.epa.gov/oppt/aegl/pubs/results80.htm. In addition, the ACGIH has recently published a notice of intended change to introduce a short term exposure limit (STEL) of 0.2 ppm for PAA to The notice is available from the ACGIH website at http://www.acgih.org/store/ProductDetail.cfm?id=2199 and marks a significant improvement in the hazard assessment information available to employers using PAA.

Knowing the exposure limit is only helpful if the actual exposure can be measured; and the ChemDAQ offers continuous monitors for PAA, designed to operate with sufficient resolution to provide protection at these low levels. Details of the monitors and the health effects of exposure to PAA are available on the ChemDAQ website http://www.chemdaq.com/gases/Peracetic_Acid.html. Contact ChemDAQ for more information at info@chemdaq.com.