The Mississippi Department of Environmental Quality has corrected an error in the wastewater pretreatment permit it issued Yokohama that would have allowed the company’s Clay County facility to discharge cadmium, a known cancer-causing agent, at a level that exceeds safe limits.
The permit — as it was issued to Yokohama Tire Manufacturing Mississippi in June 2014 — approved the tire maker’s plant to discharge the chemical at slightly excessive concentrations into West Point’s water treatment plant.
Cadmium is commonly used in batteries and found in cigarette smoke. The association between cadmium and cancer is strongest when the chemical is inhaled, but high intake from drinking water can also be dangerous, according to the World Health Organization.
The error was discovered after The Dispatch requested to review the water and air permits MDEQ issued Yokohama, which plans to open in October. The permit was changed June 5 after the cadmium limit was brought to MDEQ’s attention.
Neil Dalton, the director of Environmental Health and Safety for Yokohama, said the error was a clerical one made by MDEQ, the state agency that issues permits to industries planning to discharge wastewater into a city’s treatment system.
How it happened
West Point city ordinance only allows up to .02 milligrams of cadmium per liter to be released into the city’s wastewater treatment system. Yokohama and the city, however, asked MDEQ to allow the tire maker’s facility to release .04 milligrams of cadmium per liter.
Dalton would not comment on how Yokohama arrived at that proposed cadmium level for its West Point facility.
Carla Brown, the MDEQ engineer who wrote the permit, said it is her understanding that the requested limit originated from the Yokohama tire plant in Virginia, where a level of .04 milligram of cadmium per liter was deemed safe.
“They were sure they could meet those limits,” Brown said, noting that it is not uncommon for an industry to ask for a variance from a city ordinance.
“The city had an ordinance that was pretty old,” Brown said. “Yokohama asked if (West Point) would revisit those limits on their behalf, if they could accommodate something greater than those limits.”
West Point selectmen, during a March 2014 board meeting, unanimously voted to grant Yokohama the variance to release .04 milligrams of cadmium per liter into the city’s system.
Typically, MDEQ compares what a city proposes with its own calculations and ultimately selects the limits that are most stringent, according to Brown. MDEQ’s study suggested West Point’s system could safely receive .027 milligrams of cadmium per liter, so that number should have been the cadmium limit listed.
However, Yokohama’s permit listed .040 milligrams of cadmium per liter. That level, if released to the city’s water treatment system, could potentially violate Environmental Protection Agency guidelines.
The Dispatch pointed this out to MDEQ two weeks ago. It was then that state officials said Yokohama’s permit should have only allowed up to .027 milligrams of cadmium per liter to be released, and the permit was corrected.
What could have happened
Brown said while it is good that the Yokohama permit now contains the more stringent level, the tire maker’s cadmium output likely would not have exceeded the .027 mark anyway.
“They should be well in compliance,” Brown said.
Still, Dennis Truax, the head of Civil and Environmental Engineering department at Mississippi State University, said Yokohama may have had to reevaluate its pretreatment process if the error had not been discovered until after the facility commenced operations. Having the more stringent limits in place ensures that Yokohama and the environment will not be affected.
“If this hadn’t been changed, there was a possibility that the environment might have been impacted,” Truax said. “A slight possibility, but a possibility nevertheless. And that could have had a financial impact on the company in future years.”
Next steps
Yokohama officials will monitor the facility’s wastewater as soon as they begin discharging it, and MDEQ will compile reports within two months of their operations, Brown said.
Once the facility begins collecting data, MDEQ will do a second study of the limits to ensure the plant is meeting guidelines, according to Harry Wilson, chief of MDEQ’s permitting division.
Additionally, the city of West Point has the right to consult with MDEQ at any time and come up with new numbers if they choose to do so. Wilson and Brown said they do not anticipate any problems.
“If they meet the limits that are in the current permit — which we do have comfort that they will — then we don’t expect that there’s going to be any concern for the environment,” Wilson said.
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