On the misleading use of toxicology in discussions about fracking chemicals?

Last night I was forwarded a tweet that absolutely demanded a response. It was from that friend of science Robert F Kennedy Jr. and said “New Study: CA frak chemicals are linked to cancer, mutations and hormone disruption”. The study in question provides a case-study for science communicators and journalists alike on how activist scientists can misconstrue and miscommunicate scientific risks in order to achieve political aims. The report is titled California’s Fracking Fluids: The Chemical Recipe and the report was prepared by the Environmental Working Group (EWG). I invite readers who are unwilling to wade through the entire torrid text to browse the Executive Summary at the EWG web site. Having done so I welcome you to come back and join me as I look into the claims in a much more nuanced manner and consider the actual information provided in context.

While the others are away reading that stupefying Executive Summary I will remind the rest of you that I have spent a reasonable amount of time blogging about the investigation and communication of risk. Unfortunately, due to the nature of my blogging platform (read free and simple since I am a chemist and not a web designer) it is not terribly easy to figure out what I have written in the past so I will summarize here. I prepared a series of posts to help me out in situations like this. You see talking about how the authors have messed up the science is very hard if my audience doesn’t understand the language of the field. The posts started with “How Big and Small Numbers Influence Science Communication Part 2: Understanding de minimis risk” which explained how the science of risk assessment establishes whether a compound is “toxic” and explained the importance of understanding dose/response relationships. It explained the concept of a de minimis risk. That is a risk that is negligible and too small to be of societal concern (ref). The series continued with “How Big and Small Numbers Influence Science Communication Part 3: Understanding "Acceptable" Risk” which, as the title suggests, explained how to determine whether a risk is “acceptable”. I then went on to explain how a risk assessment is actually carried out in “Big and Small Numbers in Science Communication Part 4: the Risk Assessment Process. I finished off the series by pointing out the danger of relying on anecdotes in a post titled: Risk Assessment Epilogue: Have a bad case of Anecdotes? Better call an Epidemiologist.  Now anyone who has read all those previous posts can probably figure out what I am going to write next but that would be less fun for me so I will continue here.

Let’s get something straight right away. Fracking fluids are generally not good for human consumption. The reason for this is simple: fracking fluids are industrial mixtures intended to be used under controlled conditions. No one wakes up in the morning and asks themselves: “what shall I have for breakfast this morning: a nice chia smoothie or a glass of fracking fluid?” That being said sometimes fracking fluid can be released into the environment and so it is useful to understand its toxicity. Based on this (and political considerations) California sought to identify what was in the fracking mixtures through their law SB 4. Well the EWG report takes this disclosure and ramps up the hype (quite impressively) in order to frighten readers and sway public opinion.

The EWG report looks at the entire list of 197 chemicals that have been reported in California fracking fluids and highlights those that appear the most often. The Appendices present the entire list and some of the compounds on the list are pretty clearly not stuff you want to encounter in high concentrations: compounds like #76 toluene. A couple points should be made clear here. Fracking fluid is intended to be forcefully blown into geological formations rich in petroleum hydrocarbons. If the target geology is rich in hydrocarbons, then using hydrocarbons shouldn’t be a big deal right? It would be like complaining when someone used a hose to blast water into the ocean. The ocean is not likely to get much wetter. Moreover, toluene is reported as being used in only 3.6% of the fluid mixes and is likely used in very low concentrations, kind of like it is used in things we use everyday like glues. Thus, while it might represent a risk, it would appear to pose an exceedingly low risk. For the purposes of this blog post we will ignore these trace compounds and stick to the top 40 fracking chemicals which the EWG report highlights in Table 2. Table 2 of the EWG report presents:

The top 40 fracking chemicals used in California, Dec. 2013-Feb. 2015, compared to national data from U.S. EPA’s March 2015 report, “Analysis of Hydraulic Fracturing Fluid Data from the FracFocus Chemical Disclosure Registry 1.0.

This is the list that the authors intend to use to frighten readers and maybe if you were a non-chemist you might be frightened by the list. As a chemist I look at the list and want to yawn. It is filled with a bunch of innocuous compounds, some pretty common household-type chemicals and a handful of petroleum hydrocarbons. The actual red meat of the report is Appendix 2 which details “The environmental and human health effects of fracking chemicals used in California (2014 to February 2015)”. Clearly this is the part of the report used to cover any number of sins from the earlier text by comparing the various compounds to various regulations and health effects. 

In the report they place a particular emphasis on the California Proposition 65 List of “chemicals known as causes of cancer or reproductive harm”. To demonstrate why I have so little respect for the report let’s compare the top 40 list from Table 2 with the California Proposition 65 list. Of the 40 compounds, 5 appear on the California Proposition 65 list. You would imagine that this frightening five must be chemicals so problematic as to make you want to attend a protest and lie down in front of a fracking rig, so let’s look at these terrifying carcinogens:

 

#1 crystalline silica quartz (SiO₂)

#2 diatomaceous earth, calcined 

#7 crystalline silica, cristobalite

#23 methanol

#27 hydrated magnesium silicate (talc) 

 As a chemist looking at this list, I can’t help but wonder what the EWG author’s are actually worried about? Admittedly, each one of these compounds has a scary technical name (scary enough that someone may want to call the Food Babe) and each has been linked with cancers (often only tangentially) but certainly not in the manner and form encountered when used as a fracking fluid. This is one of the points I have tried to pound into my readers in my earlier post: a compound’s toxicity is based on mechanism of exposure and dose. In the case of each of the compounds above, the mechanism of toxicity is incompatible with any concern about exposure or even dose. Let’s look at the chemicals a bit more closely to help understand.

Chemical #1 and #7 are two types of silicon dioxide which you might know better as “sand”. Chemical #1 is the type of sand preferred for use in children’s sand boxes. Chemical #2 is a slightly more exotic version of sand that has been exposed to high temperatures and crystallized in a more fancy manner, but it is still just sand. To be clear, very finely ground sand, when inhaled, can raise your risk to cancer so the authors of the EWG report aren’t technically lying, but they are massively exaggerating the risks. As 100’s of generations of desert Bedouin will tell you, it is possible to live a lifetime exposed to sand (including sand blown in the air) without your entire population being felled with cancer. Were sand really a worrisome cancer risk then we might be less likely to use it in children’s sandboxes? To make it more misleading, with respect to fracking, the sand is encountered as part of a liquid solution/suspension. Having spent many happy days at the beach I can attest to the fact that wet sand is not easily inhaled. Anyone who looks at an inhaled carcinogen risk and compares it to fracking solution exposure either has no understanding of toxicology or is trying to mislead you.

Chemical #2 is diatomaceous earth, calcined. That is the crushed shells of diatoms that have been heat-treated to make them more crystalline. Diatomaceous earth, like sand, is a possible carcinogen when inhaled in a fine dust. It is used in industrial purposes as an organic pesticide (it is used against slugs as slugs don’t like to crawl across broken glass) in water treatment systems and interestingly enough as a toxicologically safe source of gritty material in toothpaste. So once again the EWG scientists are trying to convince the public that a chemical that we, as consumers, feel is safe enough to stick in our mouths on a daily basis, may be a danger when in a fracking solution?

Chemical #23 is methanol. Yes methanol, that ubiquitous chemical used in so many products as to be hard to know where to start. If you drink high methanol you will indeed get very ill but since we aren’t about to drink fracking fluid…I prefer the chia smoothies myself, it can also be discounted from the list.

Finally we come to #27 hydrated magnesium silicate (talc). This is a classic case of "the Food Babe effect" where a chemical sounds terrifying using its scientific name but less so by its common name. You probably have heard hydrated magnesium silicate's common name: talcum powder, used by generations of mothers and fathers to keep their newborn babies’ bottoms dry. Yes that is what the EWG scientists are trying to make you fear. An innocuous, familiar compound that most every family in America has bought and used. However, in this report it represents one of the California Proposition 65 cancer risks?

I think you get my point by now. The authors of the EWG report have taken a list of chemicals, which when used in a very different manner, have been linked (or associated) with cancer. They have then tried to use that link/association to make these chemical sound frightening when discussed in the context of fracking. I really find it hard to take a report like this seriously. The work is so clumsily done as to almost not be worth discussing except that I have already seen this report cited a half-dozen times on my twitter feed. As discussed, the people tweeting it aren’t exactly known for their scientific smarts. The first person was that tangentially famous son of a famous father who refuses to accept the toxicological research that demonstrates that Thimerosal is not a cause of autism. The second was one of my favourite science-blind progressives. I could go on, but the problem is that these people have a lot of followers most of whom also have no serious science background either and are likely to continue the stream of re-tweets. As communicators of science we have to keep shooting this bad science as soon as it appears because to do otherwise would leave the public policy morass dominated by credulous discussions of reports like this one.