Monday, November 4, 2013

The Promise of REACh to Exposure and Risk Assessment

REACh could be the most impactful piece of legislation in the history of risk assessment.  From my perspective, the jury is still out.

Below are excerpts from a chapter I co-authored with Ron Pearson and Susan Arnold that currently appears in the 2nd Editions of the AIHA book in Mathematical Modeling for Estimating Occupational Exposure to chemicals.  The chapter is entitled: REACh – A New and Important Reason to Learn Modeling

In the 1990s at meetings of the European Union’s (EU) Council of Environment Ministers, concerns were raised that European chemical policies did NOT provide enough protection to chemical product users. An evaluation of existing rules revealed that new substances were heavily regulated, but they made up only a tiny fraction of the total chemicals in commerce. On the other hand, existing substances, which made up the vast majority of the total volume of chemicals in use, were essentially unregulated. Out of this, REACh was conceived[1],[2]

This lack of risk assessment attention for existing chemicals has also been recognized on this side of the Atlantic.  It has been explicitly noted by the US EPA Board of Scientific Councilors that any comprehensive assessment of human consumer exposure to chemicals has not occurred and that the vast majority of exposures have not been systematically and proactively addressed[3].   Indeed, it is reasonably well established at this point that the risks of most types of consumer chemical exposures in modern society have not been assessed.

The types of exposure mentioned here are the exposures to chemicals that result predominately from residential sources.  Because of the leadership of the European Union and the development of REACh, we are on the cusp of a change in which regulatory mandates playing out in the rest of the world are literally driving the overall scientific development of human health exposure assessment for the multitude of common and relatively unstudied substances to which humans are exposed.

What then is REACh all about at its base level and what does it mean to the Industrial Hygienist?

REACh stands for Registration, Evaluation, Authorisation and restriction of Chemical Substances.  It is a complex piece of rulemaking that lawmakers have been hammering out in Europe for some time.  REACh became the law of the land in the EU on June 1, 2007.  Its primary purpose is to evaluate and control the human health risk from chemicals. It places the burden of proof for chemical safety on manufacturers, removing it from regulatory authorities.  Because of the complexity and broad scope of REACh, it is driving the need to screen and assess many chemicals and substances in a relatively short (but rather immediate) time-frame
So it is thus clear that REACh was conceived in Europe to regulate the majority of chemicals that exist in commerce.  What then is the upshot of REACh relative to industrial hygiene?  Professionals anticipate REACh will actually spur innovations and opportunities in estimating exposures to consumer products, which would positively affect the field of IH. Toxicologists are also facing the same issues as the second half of any risk assessment team. 

First Comes Assessment and Modeling

If  REACh requires a comprehensive and scientifically valid and rational evaluation of human exposure to substances, then modeling is an indispensable element of that assessment.   Since it has been established that this level of comprehensive assessment of human exposure to chemicals has not occurred and that the vast majority of exposures have not been systematically and proactively addressed, a considerable amount of scientific model development needs to occur.  For example, personal chemical exposures to consumers from predominately residential sources have been ignored by most chemical modelers.  Given this commitment within REACh to assessment, exposure model utilization and development should come to the forefront[4].
Exposure models are critical to any commitment for comprehensive exposure assessment because we will never be able to monitor or measure every exposure everywhere.  The need for models is particularly acute with REACh because it increases proportionally with the growing universe of chemicals under consideration. Also, as a technical expert, an industrial hygienist has a critical need for objective and rational scientific tools for analysis.  These facts necessitate both continuing education in and the ongoing scientific development of the discipline. 
Specific research needs relative to exposure model development and validation have been outlined and presented[5]; unfortunately, to date the authors are unaware of any concerted and coordinated effort to follow up on these recommendations. (Jayjock Note:  This document and web site can no longer be found online.  I will put it on my web site but in the meantime, please send me an email at and I will send you a copy).
Stripping away all the complexity, the “bottom line” for those responsible for conducting risk assessments under REACh is to provide enough quality information about any substance’s exposure pathway(s) and toxic effects in the real world to pass the “red face” test of accountability.   The size of the challenge is clearly daunting and the need for tool development is critical. 
Jayjock Comment:   This chapter was written about 5 years ago and I must say from my perspective, I have not seen a ground swell of data or researched and developed modeling tools (e.g., source characterization) coming forth.   The economic and political tides in all of this continue to shift but we can only hope that the promised progress will ultimately be forthcoming.    

 (Accessed October 28, 2013)
[2]  (Accessed January 9, 2008)
[3]    USEPA: Human Health Research Program Review: A Report of the US EPA Science Advisory Board,  Final Report of the Subcommittee on Human Health, EPA Office of Research and Development , May 18, 2005 revised July 18, 2006,  [available ONLINE] (Accessed October 28, 2013)
[4]    Jayjock, M.A, C.F. Chaisson, S. Arnold and E.J. Dederick, Modeling framework for human exposure assessment, Journal of Exposure Science and Environmental Epidemiology (2007) 17, S81–S89.

[5]     Kephalopoulos, S, A. Arvanitis, M.A. Jayjock (Eds):  Global CEM Net Report of the Workshop no. 2 on “Source Characterization, Transport and Fate”, Intra (Italy), 20-21 June 2005.  Available online:   (Last accessed January 9, 2008).

1 comment:

  1. From Pertti (Bert) Hakkinen (NIH). Disclaimer: Comments are my own and do not necessarily reflect the opinion of NIH and NLM.

    Hi Mike. The following might be of interest to the readers of your latest blog post.

    1) Another good Web link for REACH is from the European Chemicals Agency (ECHA):
    2) Here is one way to access what you have as Reference #5:
    3) Readers might be interested in these three REACH-related publications:
    “Issues in consumer exposure modeling: towards harmonization on a global scale.”
    “Risk management measures for chemicals in consumer products: documentation, assessment, and communication across the supply chain.”
    “Consumer exposure scenarios: development, challenges and possible solutions.”

    Bert Hakkinen

    Pertti (Bert) J. Hakkinen, Ph.D.
    Acting Head, Office of Clinical Toxicology
    Specialized Information Services
    National Library of Medicine
    National Institutes of Health
    Bethesda, MD USA