Category Archives: NAS

Restoring the credibility of risk assessment: A vital need under TSCA reform

By | Bio | Published: April 6, 2012

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

The primary means by which chemical risks are to be judged under current legislative proposals for reform of the Toxic Substances Control Act (TSCA), including the Safe Chemicals Act of 2011 (S. 847), is through risk assessment – a key demand of industry.  Yet traditional risk assessments have often fallen short of protecting public health and have sometimes taken decades to identify a “safe” level of exposure to certain chemicals.  As a result, public and health and environmental community confidence in risk assessment is very low.  There are also major technical deficiencies in current risk assessment methodologies that must be addressed if it is to serve as a credible basis for determining chemical risks.  For example, we now know that there are many chemicals for which any level of exposure poses some risk, yet traditional risk assessment assumes a safe level exists for nearly all chemicals.

The Safe Chemicals Act includes provisions to ensure that EPA’s use of risk assessment incorporates the best available science, initially by requiring EPA to rely on the recent recommendations of the nation’s foremost scientific body, the National Academy of Sciences, as to how EPA can improve its practice of risk assessment. Implementing the recommendations is critical to restoring the credibility of and public confidence in risk assessment. Read More »

Also posted in EPA, Policy, Risk Assessment, TSCA | Comments closed

ACC endorses cumulative impact assessment for all TSCA regulations!

By | Bio | Published: March 14, 2011

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

In what seemed a startling move, the American Chemistry Council (ACC) last week gave testimony at a Congressional hearing that included a full-throated endorsement of mandating that EPA be required to assess cumulative impacts when developing regulations addressing chemicals under the Toxic Substances Control Act (TSCA).

The call for cumulative impact assessment was a contentious element in last year’s debate over the safety standard that would apply to chemicals under a reformed TSCA.  Reform advocates supported assessing such impacts where the science allows, while ACC had staunchly opposed the concept.  The need to account for cumulative impacts is also a key recommendation of the National Academy of Sciences, in its recent reports Science and Decisions:  Advancing Risk Assessment (2009) and Phthalates and Cumulative Risk Assessment:  The Tasks Ahead (2008).

Ah, but the devil is indeed in the details:  ACC’s apparent change of heart is no such thing.  Rather, ACC is endorsing a step that would make it even harder for EPA to act to control dangerous chemicals under TSCA, namely that the agency would have to consider the cumulative impact of all prior regulations affecting a given industry before it could propose a  new one.  Read More »

Also posted in EPA, Exposure, Health, Industry, Regulation, Risk Assessment, TSCA | Comments closed

New study demands far more than a pregnant pause: Expectant women carry dozens of toxic chemicals in their bodies

By | Bio | Published: January 14, 2011

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

A long-awaited study documenting the presence of multiple toxic chemicals in the bodies of pregnant women was published today in Environmental Health Perspectives.  The study, conducted by researchers at Program on Reproductive Health and the Environment at the University of California, San Francisco, analyzed the most recent comprehensive biomonitoring data collected by the Centers for Disease Control (CDC) as part of its national human biomonitoring program.

The new study found widespread exposure of pregnant women to a large fraction of the chemicals for which biomonitoring is conducted, including chemicals that are currently in widespread use, such as brominated flame retardants (known as PBDEs) used in furniture foam and plastics, perfluorinated chemicals (PFCs) used in everything from packaging to textiles, and a pervasive environmental contaminant used in rocket fuel (perchlorate).

In particular the study noted:  “Certain PCBs, organochlorine pesticides, PFCs, phenols, PBDEs, phthalates, polycyclic aromatic hydrocarbons (PAHs) and perchlorate were detected in 99 to 100% of pregnant women.” (emphasis added)  Read More »

Also posted in Biomonitoring, Endocrine disruption, Exposure, Hazard, Health, Industry, PBDEs, Phthalates | Comments closed

Using ChAMP to Advance Alternative Testing Technologies

By | Bio | Published: June 16, 2009

Cal Baier-Anderson, Ph.D., is a Health Scientist and Richard Denison, Ph.D., is a Senior Scientist.

Many of the screening-level hazard data being collected and analyzed under ChAMP that pertain to human health are derived from traditional laboratory animal studies.  The National Academy of Sciences (NAS) recently offered a "new paradigm for toxicity testing" in its 2008 report Toxicity Testing in the 21st Century: a Vision and a Strategy.  Can ChAMP hazard data be used to facilitate the development of new testing strategies?  Read More »

Also posted in ChAMP, EPA, In Vitro, Testing | Comments closed

The Next Mile Marker on the Road to High Throughput In Vitro Screening?

By | Bio | Published: June 24, 2008

John BalbusJohn Balbus, M.D., M.P.H., is Chief Health Scientist.

A new paper by Shaw et al., published in May in the Proceedings of the National Academy of Sciences, “suggests a generalizable and scalable method for the systematic characterization and comparison of novel nanomaterials” using high throughput in vitro tests.  Does this mean that the National Academy of Sciences’ vision for toxicity testing in the 21st century – proposed for conventional chemicals – is already here for nanomaterials?  Not quite.  Read More »

Also posted in In Vitro, Nanomedicine, Research, Testing | Comments closed

On the Road to In Vitro Testing: Are We There Yet?

By | Bio | Published: March 18, 2008

John BalbusJohn Balbus, M.D., M.P.H., is Chief Health Scientist.

EPA’s recently released draft Nanotechnology Research Strategy (NRS) proposes a tiered testing system to evaluate human toxicity of nanomaterials.  It puts in vitro tests, or those done in test tubes and petri dishes as opposed to living animals, front and center.  EPA says the results of the first, in vitro tier will be used for guidance on “what health endpoints to monitor” and the second, in vivo tier will then help “identify those in vitro assays that correlate with in vivo nanomaterial toxicity or health effects.”

Wait a second.  If the in vivo testing is necessary in order to figure out what the in vitro testing results really mean, how can the agency use the in vitro testing results to figure out what health endpoints to monitor?  This cart and horse confusion is a serious matter. Read More »

Also posted in EPA, Research, Testing | Comments closed