EDF Health

Selected tag(s): exposure and hazard

EDF comments at National Academy of Sciences workshop on “weight of evidence” in chemical assessments

Richard Denison, Ph.D., is a Senior Scientist.

This week I attended a workshop sponsored by the National Academy of Sciences’ Committee to Review the IRIS Process.  This committee was established in response to a rider attached to an “omnibus” spending bill passed by Congress in late 2011.  The committee’s charge is to “assess the scientific, technical, and process changes being implemented by the U.S. Environmental Protection Agency (EPA) for its Integrated Risk Information System (IRIS).”

EPA describes IRIS as “a human health assessment program that evaluates information on health effects that may result from exposure to environmental contaminants.”  The key outputs of IRIS assessments are one or more so-called “risk values,” quantitative measures of an “acceptable” level of exposure to the chemical for each cancer and non-cancer health effect associated with the chemical.  IRIS risk values are in turn used by regulators to set everything from cleanup standards at Superfund sites to limits in industrial facilities’ water discharge permits.

This week’s workshop – a detailed agenda is available herewas intended to provide expert input to the committee to inform its review of IRIS.  It focused on the complex and controversial issue known as “weight of evidence” (WOE) evaluation.  Here WOE refers to how EPA – in conducting an IRIS assessment of a particular chemical – selects studies, evaluates their quality, and assesses and integrates their findings, as well as how it communicates the results.  At issue in particular in a WOE evaluation is how the assessor determines the relative importance – or weight – to be given to each study.

One of the many issues that came up in the discussion of WOE is how to identify and assess the “risk of bias” in individual studies – a concept borrowed from the evaluation of the reliability of clinical trials used in drug evaluations.  (See this Powerpoint presentation by one of the committee’s members, Dr. Lisa Bero, which provides a nice overview of risk of bias in that setting).  Evaluating a study’s risk of bias is critical for assessing its quality and in turn the weight it should be given, because bias in studies can result in significant under- or overestimates of the effects being observed. 

One type of bias is so-called “funder bias.”  Dr. Bero and other researchers have documented through extensive empirical research that there is a significantly increased likelihood that a study paid for by a drug manufacturer will overstate the efficacy or understate the side effects of a drug.  As to studies of environmental chemicals, at the workshop and more generally, the chemical industry has pointed to adherence to Good Laboratory Practice (GLP) standards as a sufficient antidote to bias, including funder bias, a notion that has been heartily disputed by others.

But enough background.  My intent here is not to fully describe the workshop discussions, but rather to provide the comments I presented during the public comment period at the end of the meeting.  My comments addressed the issue of funder bias and also sought to urge the committee not to dive so deeply into the weeds in reviewing and proposing enhancements to EPA’s IRIS process that it loses sight of the need for a workable IRIS process that is able to provide in a timely manner information so critical to ensuring public health protection.

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The chemical industry says formaldehyde and styrene don’t cause cancer. Only one of 52 scientists agree.

Richard Denison, Ph.D., is a Senior Scientist.

Last week, the National Academy of Sciences (NAS) held a joint meeting of its two panels that are charged with reviewing the listings of formaldehyde and styrene as carcinogens in the 12th Report on Carcinogens, which was released in June 2011.

The 12th Report on Carcinogens (RoC) is the latest edition of a Congressionally mandated report developed by the National Toxicology Program (NTP).  It upgraded formaldehyde to the status of “known to be a human carcinogen,” and for the first time listed styrene as “reasonably anticipated to be a human carcinogen.”  That put the chemical industry into a real tizzy, what with the threat these listings pose to its profits from the huge volumes of these cash cows sold each year, not to mention the huge potential liability it faces.

Never one to go down lightly, the American Chemistry Council (ACC) has launched an all-out assault on the NTP and the RoC.  It is waging battle not only with the executive branch, but also in the courts and in Congress.  In late 2011, it managed to get its allies in Congress to slip into the Consolidated Appropriations Act of 2012, without any debate, a rider that mandated the NAS reviews of the formaldehyde and styrene listings in the 12th RoC that are now underway.

ACC also pushed legislation in the last Congress to shut down all funding for the RoC until the reviews are completed; failing on that front, earlier this month it demanded that NTP cease all work on the next (13th) edition of the RoC.  (For more background, see previous blog posts by EDF and NRDC.)

Lost in all this kerfluffle, however, are these salient facts:

  • The formaldehyde and styrene listings are the outcome of one of the most extensive scientific assessment processes on the planet, entailing reviews by four separate groups of expert scientists for each chemical.
  • ACC as well as the public had at least three separate formal opportunities for providing input to these expert bodies.
  • Of a total of 52 votes cast by these scientific panels on the NTP’s recommended listings, 51 of those votes supported the recommendations and only one opposed them. Read More »
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“Toxic Clout” shines a much-needed light on the chemical industry’s undue influence over toxic chemical decisions

Rachel Shaffer is a research assistant.

Remember the 2000 hit film, Erin Brockovich?  It was the Hollywood version of a real-life investigation into the contamination of groundwater in Hinkley, California with a known human carcinogen called hexavalent chromium (or hexchrome for short).  

Well, hexchrome is back on (a slightly smaller) screen, this time featured in a two-part series by the Center for Public Integrity (CPI) and PBS NewsHour.

The series, which aired on public TV stations earlier this month, highlights the continuing problem of hexchrome contamination around the country, including the still-unresolved situation in Hinkley.  Some 70 million Americans are exposed to this carcinogen through the water they drink. 

But the program also dives into another, even more concerning problem:  Years of delay in finalizing EPA’s risk assessment for the toxic metal, a prerequisite to any effective regulation.  Why the delay? Unfortunately, it’s an all-too-familiar story:  the chemical industry is stalling the process.  

And what are the consequences?  As EDF’s Senior Scientist Dr. Richard Denison says in the series:  “Decisions delayed are health protections denied.”  The chromium standard for drinking water has not been updated since 1991 and does not reflect recent scientific findings indicating that the standard needs to be significantly lowered to protect public health.

Check out the CPI/PBS segments (links below) and the related articles in CPI’s Toxic Clout series, which is part of an ongoing investigation of excessive industry influence in science and policy.

                Part 1: Science for Sale

                Part 2: Decision Delayed on Dangerous Chemical in Drinking Water

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Regrettable, if predictable: Bisphenol S mimics estrogen just like its better-studied cousin, bisphenol A

Richard Denison, Ph.D., is a Senior Scientist.

A rule of thumb in chemistry is that chemicals that look alike will more often than not act alike.  (If it looks like a duck … .)  Indeed, when chemical companies are faced with testing requirements for one of their chemicals, they routinely argue that they should be allowed to submit test data on a structurally related chemical instead. 

So when it was revealed that companies making products (such as thermal receipt paper) that contain the estrogen-mimicking compound bisphenol A (BPA) were switching to another chemical called bisphenol S (BPS), many scientists’ eyebrows quickly arched.  Read More »

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No way to treat our kids: Formaldehyde, flame retardants and other toxics exceed safe levels in air and dust in day care centers

Richard Denison, Ph.D., is a Senior Scientist.

A study conducted by the State of California [Update 10-26-12:  The study was funded by the California Air Resources Board and conducted by Asa Bradman and colleagues at the Center for Environmental Research and Children’s Health at UC Berkeley] – described as “the first comprehensive study in child care centers to measure a broad spectrum of pollutants including many volatile organic chemicals, particles, and pesticides, and emerging pollutants such as flame retardants, phthalates and perfluorinated compounds” – has routinely detected dozens of these toxic contaminants in the air or floor dust present in such facilities. 

Some of the key findings include the following:

  • “Formaldehyde levels in 87% of the facilities exceeded the California acute and chronic reference exposure guideline levels for non-cancer health effects such as respiratory and sensory irritation (e.g. eyes, nose, throat, and lungs).”
  • “In most facilities, levels of formaldehyde, acetaldehyde, chloroform, benzene, or ethylbenzene exceeded child-specific Safe Harbor Levels computed by the report authors based on Proposition 65 guidelines for carcinogens.”  [These are levels calculated to result in a cancer risk of at least 1 per 100,000 people.]
  • “Phthalates, flame retardants, pesticides, perfluorinated compounds, and lead were also frequently detected in dust and/or air.”
  • “Child dose estimates from ingestion of dust for two brominated flame retardants (BDE-47 and -99) exceeded the non-cancer U.S. EPA reference health dose (RfD) in 10.3% of facilities for children < 1 year old.”
  • “Two VOCs commonly found in cleaners and personal care products, d-limonene and decamethylcyclopentasiloxane, had the highest concentrations compared to other chemical groups.”

The presumed sources of most if not all of these chemicals are everyday materials and products used to construct, furnish or clean these facilities.  Formaldehyde, for example, is used in hundreds of materials and products, including furniture, wood products, carpeting, paints, and household cleaning products.  California took action in 2007 to limit is use in pressed wood products, and Congress passed a law in 2010 to do the same.  (Unfortunately, the proposed regulations needed to implement the federal law – which Congress mandated be in place by January 1, 2013 – are stuck in regulatory review limbo at the Office of Management and Budget (OMB):  The proposed regulations were sent by EPA to OMB’s Office of Information and Regulatory Affairs (OIRA) more than 170 days ago, on May 5 of this year, but remain under “pending review” by OIRA despite the requirement for OIRA to complete its reviews within 90 days.)

The larger problem exposed by the California study demands, of course, a far more comprehensive solution – TSCA reform.

 

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The Sweet Smell of … Cardiovascular Hazards?

Kyle Ward is an intern in EDF’s Health Program.  Jennifer McPartland, Ph.D., is a Health Scientist.

When you think of air fresheners what is the first thing that comes to mind?  Fresh spring flowers?  French vanilla?  Reduced Heart Rate Variability?  While that last one may not be on everyone’s mind, it certainly has been for one team of scientists.  They have recently conducted the first study ever to examine the potential for exposure to household cleaning sprays, air fresheners and scented products to adversely affect people’s cardiovascular systems.  Their findings, published in last month’s Environmental Health Perspectives, show a linkage between long-term use of household sprays and scented products and reduced heart rate variability (HRV).  Reduced HRV is associated with increased risk for a host of negative health effects ranging from heart attack to death.   Read More »

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