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PFOA: The Forever Chemical?

You probably have heard a lot about the chemical PFOA (perfluorooctanoate), sometimes called the “forever” chemical. PFOA is a simple 8-carbon molecule that has fluorine atoms attached rather than hydrogen atoms. As a result PFOA resembles several fats found naturally in our bodies, but it does not break down to any significant extent. Although PFOA does not occur in nature, it is a very useful tool for firefighters in putting out electrical and oil fires that cannot otherwise be doused with water. And because it is chemically stable it has been used in a variety of household products, such as carpets and food wrapping. Due to its extensive use in so many areas of our lives, very low concentrations are found in our bodies, our houses and our environment. In a few places, these levels may be harmful.

This chemical has been studied A LOT, and for all the study, a big problem has emerged: There are large differences in government opinions as to what the safe level of PFOA actually is according to recent international meeting. Sometimes these differences are as much as 750-fold. These differences are principally due to two issues. First, the determination of PFOA’s safe dose depends, in part, on establishing its first toxic effect in experimental animals, such as a change in liver enzymes, and government agencies, even within the US disagree. Second, the time it takes for PFOA to leave our bodies is generally much longer than that measured in experimental animals. This longer half-life lowers PFOA’s safe dose estimate for us.

This is a prime example of what environmental risk assessment is all about. PFOA is an important and very useful chemical, particularly for firefighters, but as with any chemical, too much may be harmful. Do we eliminate the products and its use in electrical and oil fires, or try to determine, collectively, a safe level for our environment? Trying to determine a more uniform safe level seems to be the better course. However, this is a difficult task, and so it would make sense that governments and other organizations work together to accomplish this goal. 

Recently, an international scientific collaboration has resulted in a consensus position on the time required for half of the PFOA to leave our bodies, and it is not nearly as long as other groups think. This is good news, but like any science, this consensus needs to undergo peer review during submission for publication later this month. In the meantime, this consensus may alleviate part of the differences in opinion among government groups and lead to more uniform estimates of PFOA’s safe dose. Additional collaborative work should also be started in other areas of scientific differences.

WEEL OEL

Occupational Exposure Limits (OELs) are designed to safeguard the health of healthy workers during their careers. These limits are based on the assumption of repeated daily exposure throughout a working lifetime, typically averaged over an 8-hour workday. Their purpose is to prevent both immediate (acute) and long-term (chronic) health issues arising from workplace exposures. It’s important to note that OELs are not intended for the general public, which includes vulnerable groups like infants, the elderly, and those with pre-existing health conditions.

Workplace Environmental Exposure Levels (WEELs) are health-based guidelines for chemical hazards in the workplace. These values represent air concentrations believed to protect the majority of workers from negative health effects resulting from occupational chemical exposure.

The WEEL Process
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The development of new or revision of existing WEELs is typically assigned to voluntarily designated subcommittees. A subcommittee usually comprises 3 – 4 members from the WEEL Committee. New WEELs are developed using the OARS-WEEL administrative standard operating procedure (SOP), while existing WEELs are usually revised every 10 years, unless the availability of significant new data which may impact the existing WEEL value compels the committee to make a revision sooner. The OARS-WEEL SOP contains procedures and guidelines governing conflicts of interest, draft document preparation, literature searches, draft document review, balloting process, post-ballot WEEL documentation quality assurance scientific review, and publication.

Once a subcommittee has prepared a draft WEEL document, a review of the draft is scheduled for the next available Committee meeting. The WEEL Committee members are expected to have reviewed all such drafts prior to the meeting. If no major changes are necessary to a draft, the attending Committee membership may, by a simple majority, approve the WEEL for balloting. Alternatively, the Committee may direct the subcommittee to revise the WEEL and present it for further discussion at a future meeting. If a ballot is not approved by a two-thirds majority of non-abstaining Committee members, it is discussed at the next Committee meeting to determine the appropriate course of action. Once the WEEL is approved by a two-thirds majority of non-abstaining Committee members, copies of ballot comments are forwarded to the designated subcommittee and all substantive comments must be addressed in the final draft. If resolution of a substantive comment results in a change to the WEEL value or a change in the basis for the value, the draft must be re-balloted.

Once all comments have been addressed on a successfully balloted draft, document formatting and editorial review are performed by TERA, before the draft WEEL document is made available for public comment (usually for a period of 30 days but may be extended if the need arises). After the public comment period has elapsed, comments are addressed by the subcommittee responsible for that specific draft, after which the WEEL documentation is submitted to Toxicology and Industrial Health (TIH), a peer-reviewed medical journal that covers research in the fields of occupational health and toxicology, for publication. A thorough review of the galley proof by the scientific content quality coordinator at TERA, and proofreaders and editors at TIH is the penultimate step before eventual publication of the WEEL documentation.

The WEEL Committee

The OARS-WEEL Committee is composed of volunteer experts specializing in the scientific determination of occupational exposure levels. This committee actively seeks a balanced representation of professionals from toxicology and industrial hygiene, drawing upon a diverse range of experience from industry, government, academia, and consulting. Importantly, each member contributes to the Committee based on their individual expertise and not as an official representative of their respective employer, organization, or agency.