Letter: What really caused the mill’s dank odor

May 16, 2023

This in reference to the article "Identity Crisis: Can Canton Still Be a Mill Town Without a Mill?" in the May 10 Mountain Xpress.

As a former process and production manager at the mill, I thank you for a very well-written and informative article.

There was one serious error in the reporting. The article's statement of "an infamous dank odor caused by hydrogen sulfide and other reduced sulfur compounds" is incorrect.

Hydrogen sulfide (H2S) is an extremely toxic, deadly, insidious gas. It has a characteristic rotten-eggs smell. However, after the first whiff, the gas numbs the olfactory senses, and it can no longer be smelled. This H2S gas and other reduced sulfur compounds are generated in the chemical pulping and recovery processes of the mill. These processes are extensively sealed and vented to collection/combustion systems in the mill. There are H2S alarm sensors, sensitive to H2S levels less than 5 parts per million, located throughout the process to monitor for any escaped H2S gases. Mill personnel are trained in response to the alarms.

There is no way H2S escapes the mill to the ambient air.

The infamous dank odor referred to is typically due to mercaptans, which are also sulfur compounds with a rotten eggs, boiled cabbage odor. The olfactory senses can detect mercaptans at extremely low (ppm, even parts per billion) concentrations, which invariably escape the mill combustion systems through discharge stacks.

You can often smell them in Enka and West Asheville.

The low-concentration mercaptan gases, though unpleasant, are not considered a health hazard.

— Bill MillerBiltmore Lake