Understanding risk: A reasonable level of certainty

I love what the EWG is doing. The EWG website has multiple guides for consumer products from makeup to cleaning products. The products are easy to search and clearly rated. Having all of the available data put together in one easy-to-search place is an invaluable aid. The EWG is also doing a good job of getting the message out there that not everything in consumer products is consumer friendly. However, the website does not replace common sense.

Let's review.

The precautionary principle says that if there is a reasonable belief of risk and there is an acceptable alternative, then use the acceptable alternative. This sounds simple, but in practice it can be difficult to interpret and apply to daily life. What is a "reasonable" level of certainty that the risk exists? What level does the risk need to surpass before I believe it is a clear and present danger? How convenient and available must the alternative be before I switch over?

In a previous blog article I talked about zero risk. The main point of the article is that there is no such thing as zero risk. But what is a reasonable level of certainty that the risk exists?

The principle I follow is that if the manufacturing process uses traditional methods and there is little evidence of harm, then the product is okay. Here I mean traditional methods to be those involving physical changes (e.g., freezing, drying, pulverizing into a powder) and well established chemical changes (fermenting, roasting, and so on). If the manufacturing process is relatively new (I'm thinking last 50 years as "new"), then more substantial proof is needed to affirm the safety of the product. If the process is extremely new (let's say last 10-20 years) and involves a radical departure from traditional methods (e.g., genetic changes or extreme chemical changes), then very substantial proof is needed.

For example, there have been very few long term studies on the risks of gmo foods. Because gmos are so new and represent such a large departure from normal practices, I personally feel that more proof is needed to establish the safety of such products. Similarly, I feel that many of the chemicals produced for or as a byproduct of plastics need similar vetting before I can deem them safe.

Here is a counter example. Retinyl acetate is listed on the EWG as an 8 (0 being the best and 10 being the worst for cosmetic products). Retinyl acetate is more commonly known as vitamin A. Clearly, vitamin A has been around for a long time and is vital for normal functions of the body. However, because it is fat soluble too much vitamin A can lead to problems. Lathering your entire body in pure vitamin A every day would quickly lead to high levels of toxicity. Yet it is not clear to me that the level of vitamin A in these products is likely to lead to such high levels of build up. So, knowing that there is vitamin A in a product, by itself, is not enough information to be useful.

Here is another counter example. EWG lists lavender oil as a C (A being best and F being worst for cleaning products). However they present no evidence as to how or why lavender oil is bad (except perhaps that there are no studies on it?). Some of the cleaning products are listed as bad merely because they do not list all of their ingredients. I am in favor of clear and complete labeling, but the absence of complete labeling does not automatically mean that the product is going to cause me harm.

Conclusion: EWG is doing a great job of making valuable information accessible. However that does not replace our need to understand risk -- both its certainty and its level.