I object. “Toxic,” which is a perfectly good word, is being misused in the media where it is used most often to simply demonize chemicals and hydrocarbons. Toxic is commonly used as a synonym for “dangerous” or “life threatening” without regard for actual dangers. Although we know that some compounds are life threatening even in very small doses “a central concept of toxicology is that effects are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect.” In other words, if we are going to use “toxic” or “toxicity” with some precision then we have to include context by describing dosage or exposure over time. Without that context the word just invokes the monster that’s hiding in the closet.  

So when we read a sentence like this one: “The state [Vermont] alleges that these [oil] companies used the toxic gasoline additive, MTBE (methyl tertiary-butyl ether), knowing that it ‘posed a devastating risk’ to the state’s water supplies.” We should be prompted to ask some questions: Toxic at what concentration? Does this concentration occur in nature? Does it occur in industrial facilities? Toxic over how long an exposure period? Is it toxic at levels typically experienced by consumers?

A few minutes of research would have revealed that no scientific study has concluded that MTBE is a carcinogen or a genotoxin at concentrations found in groundwater and that short term peak exposures of 200,000 parts per billion “did not indicate concerns”. Further, “the risk characterization for MTBE does not indicate concern for human health with regard to current occupational and consumer exposures.” So, unless you know someone that who is drinking over 60 gallons per day of MTBE-contaminated water (20 ppb), which would get them close to the exposure limit of 5 mg per day (with safety factor of 20), let’s drop the reflexive use of the word “toxic” to describe chemicals and reserve its use for times when the appropriate context can be provided.

Maybe next time we can discuss how we might know when to label a risk as “devastating.” 

Jeff Hazle

Posted by Jeff Hazle

Jeff Hazle is the former Senior Director of Refining Technology for AFPM. To learn more about AFPM, visit AFPM.org.