Johnson Utilities wastewater treatment

A Johnson Utilities wastewater treatment plant in San Tan Valley has been the source of many complaints over the odor that has made its way into housing areas.

SAN TAN VALLEY — The county is taking action on residents’ fears that the stench coming from the Johnson Utilities sewer treatment plant is more than gross, but also toxic.

On Wednesday the county installed one of two planned additional hydrogen sulfide monitors on the north side of East Oasis Boulevard.

The second monitor’s location will be based on an analysis by the Arizona Department of Environmental Quality determining where the concentrations of hydrogen sulfide should be high. It should be installed shortly, the county said.

The location of the new monitor on the north side of East Oasis Boulevard is aimed at addressing residents’ concerns that the county’s monitoring that showed there has been only one violation since July 24, 2017, has been faulty due to the location of the existing monitor, which was in a maintenance shed at the nearby golf course.

Many homes are in between the plant and the maintenance shed, leading activists to charge that given that hydrogen sulfide is heavier than air, it could be blocked by a row of homes from reaching the current monitor in high concentrations. Residents also note anecdotally that the smell gathers in different parts of the community very differently depending on daily conditions.

“There is an open field in my backyard,” said John Dantico, who lives near the plant and has worked to pressure officials to take action against Johnson Utilities. “I can smell it inside my house, but if I get outside my front door, I can’t smell it. They know that.”

Mike Sundblom, director of Pinal County Air Quality, said he believes that the initial monitoring was representative of the gas levels experienced by the population in that area.

The recent volume of complaints prompted ADEQ to visit the area on three occasions since Jan. 20. In a letter to residents who filed complaints, ADEQ said that although odor was noted and the wastewater treatment plant was “out of compliance,” that “based on the current data, no adverse health effects, such as decreased respiratory function, are expected among the exposed population. Some people may smell unpleasant odor and feel discomfort at the detected levels.”

ADEQ did not explain what data it based its conclusions on and added that it was reviewing additional data provided by the utility.

“You may feel discomfort. That’s a health issue,” said Matt O’Connell, who lives by the plant. O’Connell said that symptoms of physical discomfort caused by the odor and the presence of hydrogen sulfide are a cause for concern that is not being adequately addressed given the symptoms being reported by residents.

He has organized a group of concerned residents called The United Citizens, Clean Air Clean Water. They have begun meeting regularly with Pinal County Supervisor Mike Goodman, R-San Tan Valley, and are working to take action on the issue.