A Brief History of PAHs in the Environment -and a Regulatory Headache

Polycyclic aromatic hydrocarbons (PAHs) are thought to account for about 20% of the carbon in the universe (see here, here, and here) and are considered building blocks of life. On Earth, PAHs occur in organic matter, including fossil organic matter (oil, coal), and are constantly being made when organic matter is heated or decays. They are also constantly being destroyed – eaten by microorganisms, degraded by the sun, other natural processes.

PAHs cause headaches for both regulators and the regulated. The headaches are rooted, in part, in history, so this post is a brief introduction to the history of PAHs in the environment, with an example of a regulatory headache exacerbated by government scientists who misrepresented historical data.

Generally speaking, no one makes PAHs on purpose – they are just part of the raw materials and byproducts of modern life. In addition to being present in oil and coal, PAHs are made in wood-burning fireplaces and stoves, in engine lubricants, in compost heaps, in decaying plants in a swamp… wherever organic matter is heated. Thus, humans are now and have, since fire was tamed, been exposed to PAHs. As one researcher put it: Continue reading


EU court overturns aquatic toxicity classification, putting another hole in EPA’s Relative Potency Factor approach to PAH mixtures

Posted by Anne LeHuray, October 11, 2015

In a rare win for science, the subscription news service Chemical Watch reports that

The European General Court has annulled part of the mandatory classification of the substance CTPHT [coal tar pitch, high temperature], following an appeal by 18 companies.

Its ruling means CTPHT is no longer classified as a substance with category 1 acute and chronic aquatic toxicity…

In its written opinion, which is available here, the Court took note of the very low aqueous solubility of coal tar pitch, which is in contrast with the assumption made by European Chemical Agency’s (ECHA’s) Risk Assessment Committee (RAC) that all of the individual PAHs dissolved in water and were therefore available to aquatic biota. According to the Court’s opinion, the highest tested actual solubility of coal tar pitch was 0.0014%, but the European Commission accepted ECHA’s individual polycyclic aromatic hydrocarbon (PAH) constituent method as the basis of the “category 1 acute and chronic aquatic toxicity” classification. The PAH constituent method resulted in a calculated solubility of 9.2%. The Court concluded

…such a value is not realistic, given that the maximum rate is 0.0014%.

According to Chemical Watch, the Court’s ruling is a landmark case in the EU because, apparently for the first time, it sets limits on the discretionary powers of EU government agencies when assessing chemical risks.

The ruling has significance to how the US EPA assesses PAHs as well. Continue reading

What Can Hubble See? Find Out in This Music Video

The Hubble space telescope – it’s been an amazing 25 years!

Lights in the Dark

Get into a little “Hubble trouble” with this music video by NPR’s Adam Cole, aka Skunk Bear. Produced in honor of the 25th anniversary of the space telescope’s launch aboard Discovery STS-31 on April 24, 1990, the video is a parody of Iggy Azalea’s “Trouble” and, in my opinion, surpasses it astronomically.

(See what I did there?)

Enjoy, and Happy 25th Anniversary Hubble! Also, check out a video of the STS-31 launch below:

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Is the Department of the Interior’s Scientific Integrity Office Protecting Scientific Integrity?

Posted by Anne LeHuray, March 16, 2015

Federal agencies disseminate vast quantities of information that is not subject to public notice or comment, but often has the effect of regulation. A good example is the Food and Drug Administration’s (FDA) decades-long recommendation to reduce dietary salt for better health. For over 40 years, Americans struggled to reduce salt intake, only to learn in 2013, after a comprehensive review commissioned by the Centers for Disease Control that, in fact, there is no evidence that reducing salt improves health outcomes. Indeed, the review suggested that more salt in the diet might be a good thing. Continue reading

Abuse of Science in Texas: Secret Science Reform Needs to Apply to More than Just EPA

Posted by Anne LeHuray, February 21, 2015

Originally published by American Thinker (November 26, 2014)

On November 19, 2014, the House of Representatives passed HR 4012, the Secret Science Reform Act of 2014. The bill would prohibit the US Environmental Protection Agency from regulations based on “science that is not transparent or reproducible.” Hooray! Reproducibility is the touchstone of science. Transparency is the way to ensure that scientists who want to reproduce another scientist’s results can try to do so. No scientist anywhere would argue against reproducibility, nor should any scientist argue that research results used to make regulatory decisions (such as drug approvals, emission limits, product bans) be exempt from transparency. Unfortunately transparency has not always been a priority. Examples of the current reproducibility crisis in the sciences can be found here, here, here, here and here. A requirement to use transparent, reproducible science should apply to all government agencies, not just EPA. The government need not replicate the science itself, just make sure the information needed for reproducibility is readily available. Just one of the many examples from the pavement coatings industry’s decade-long effort to obtain data from the US Geological Survey illustrates the point. Continue reading

Science Meets Regulation

Posted by Anne LeHuray, April 11, 2013

The working world I inhabit is hard to explain to outsiders.  Regulations that govern many aspects of doing business are governed by application of laboratory or theoretical science to the real world.  Sometimes figuring out science-based regulation is easy – an exercise in applying well understood physical principles to engineering design to, for example, calculate safe light bulb wattage for a lamp or construct an effective pressure release valve for a water heater.   But using science to develop environmental regulation?  First, various branches of science had to be invented from scratch or vastly expanded.  The U.S. Environmental Protection Agency was founded in 1970 to focus on protection of the environment.  EPA’s website has a “history” section that goes into the the founding of the Agency and major milestones since.  Continue reading