9 Assumptions We Make About Chemicals

All things considered, I’m not a particularly paranoid person. Not all of my food is organic, there’s fluoride in my toothpaste, I breathe in way too much clay dust, support vaccination, and at a time when everyone is shunning the evils of gluten, I’ve taken up baking bread. (Chewy, crusty bread that crackles when taken out of the oven…) However, given inevitable gaps in scientific knowledge and human fallibility, I and many other environmentally concerned people support the precautionary principle.

But given how many headlines from my Twitter feed scream about carcinogens, infertility, asthma, and other diseases, I have to wonder: are we being rational in how we look at chemicals and evaluate our risk from them? Or is this some kind of knee-jerk reaction?

I recently read (and reviewed) an eye-opening book on toxicology called The Dose Makes the Poison by Patricia Frank and M. Alice Ottoboni. It’s no page turner, but it offers a perspective on toxins that squarely contradicts the more usual alarmist headlines that show up in my environmental Twitter feed. Its conclusion: public perception of chemicals and risk have very little correlation with what the scientific data show. Although I do feel like the book downplays potential risk, especially from combined chemical exposure, it also exposes the press and public’s tendency to consider chemicals in a black/white dichotomy.

I felt very defensive while reading this book, but after that first reaction, have come to recognize that it made valid points and shook up some assumptions I didn’t even know I was making. Are you looking for some food for thought? Here are some of the myths the book takes pains to point out and disprove.

1. Natural = safe. In fact, many of the most toxic substances on this planet are entirely natural. From death cap mushrooms and oleanders to hemlock, arsenic to radon, nature’s pharmacy is much, much bigger than man’s. And frequently bad for us. Humans have been poisoning themselves (accidentally) and others (not accidentally) for our entire history as a species, long before we were able to create synthetics.
2. Chemicals are bad. Even if you’re only talking about synthetic chemicals, this is a pretty broad generalization. Manmade chemicals include pesticides, poisons, and life-saving medicines.
3. Substances are inherently safe or unsafe. You can die from drinking too much water, eating too much spinach, drinking too much coffee, or taking too much Tylenol. Hell, the chemical acrylamide, produced by frying, baking, or roasting starches, is carcinogenic. Granted, you’d have to drink or eat a lot of these substances, but the point is: there’s a threshold after which they stop being harmless or therapeutic and become dangerous. With relatively few exceptions, chemicals have measurable thresholds. It’s the dose that makes the poison. 
4. Correlation equals causation. In one case study, a new hospital was experiencing a spike in the rate of newborn jaundice. Everyone suspected the culprit was pesticides sprayed on the farms outside. However, nearby hospitals exposed to similar levels of the same pesticides didn’t have increased jaundice cases. Eventually, they figured out that babies at the new hospital, which had fewer windows, were less exposed to light. Phototherapy is now effectively used to treat jaundice.  It’s both easy and tempting to jump to conclusions, but correlation does not always equal causation, certainly not to the extent the press makes it seem. The next time you read an article about how x substance causes x disease, it might be worth considering whether the article is really about a correlation, not a proven cause.
5. Banning a chemical is the safest way to go. Well…sometimes. And then sometimes it just makes manufacturers switch to a less well tested substitute, and we’re faced with choosing between the known risk (e.g. BPA) and the unknown one that we have much less information on (BPS). Joy.
6. Anyone who doesn’t condemn synthetic chemicals is an industry apologist. Dismissing anyone who disagrees with your beliefs as incompetent or corrupt is a devastatingly effective way to stop making rational evaluations. There are certainly industry apologists. However, there are also studies — lots of them — that simply don’t yield conclusive results, show that a chemical used at its recommended level is safe, or that its benefits outweigh its risks (as with many medicines).
7. Studies can give us definite yes or no answers about how safe chemicals are. Sometimes, but not very often.  Toxicological testing often requires so much time and resources  in order to draw statistically valid conclusions that the amount of funding provided just isn’t enough. So we end up with plenty of studies that suggest possible conclusions without being statistically valid, yet are interpreted by the press to be a definite conclusion.
8. Looking at one source can give us definitive answers about how much risk we face. It’s hard to get a balanced perspective by looking at just one website or one study, even if you haven’t leaped to any of the above conclusions. Did you know that 79% of the Society of Toxicologists surveyed consider the EWG (home of the Skin Deep database) to overstate the health risks of chemicals? I didn’t either. But knowing that will help me evaluate how much risk I think my shampoo is putting me in. I recommend also checking out Personal Care Truth for another perspective on cosmetics safety.
9. Organic farming does not involve pesticides. Some small farms do use crop rotation and other pesticide-free ways to manage pests, but most larger scale organic farms use pesticides. The main difference is that they are required to use organic pesticides rather than synthetic ones. (Mostly.) However, there’s some evidence to suggest that organic pesticides are not necessarily safer for humans or ecosystems than their conventional counterparts, and some biodegrade into other chemicals that are harmful. Dammit, why can’t things be straightforward for once?

I’ve read that the human bias is to believe that we are in peril, which back in the good old days was less likely to get us killed than dismissing a potential threat. I also think we have a lot more information at our disposal now and should use it to make rational, well-considered judgments instead of just reacting. Life would be so much simpler if buying organic was always better for the planet, or if all synthetic chemicals were dangerous. Instead, it’s about a whole bunch of case-by-case decisions, like having to judge people as individuals instead of lumping them into stereotypes. No one said it was going to be easy.

What’s your attitude towards chemicals? Have you found yourself falling into any of these assumptions?