Jeffrey D. Allred, Deseret News
Stericycle medical waste incineration plant in North Salt Lake City Thursday, May 30, 2013.

Some critics of Brian Moench's recent My View column about Stericycle demonstrate a disturbing ignorance about how scientists conduct research ("Stericycle should stop incinerating," July 26). Some readers commented that the science Moench cited in his piece was "soft" and that the studies only show an "association" between pollution, like Stericycle's emissions and negative health impacts.

Scientifically proving causation is incredibly difficult. The gold standard is a randomized, double-blind, placebo study. No ethical academic institution anywhere would allow researchers to conduct such a study on humans. For one thing, they'd have to find volunteers willing to be exposed to known poisons in a clinical environment. Do I have any volunteers? I didn't think so. Researchers can only observe real-world situations and draw their conclusions based on messy, complicated, real-life outcomes. In this sense, we are all unwitting research subjects in one big experiment.

So the real question to the doubters is how many children near the pollution source have to fall ill before we believe the strong association between emissions and poor health outcomes? Note that there has also never been a randomized, double-blind, placebo study to prove that smoking causes cancer, yet we all accept that smoking is deadly.

Ingrid Griffee

Salt Lake City