Yokohama’s tire manufacturing operation in West Point is asking the Mississippi Department of Environmental Quality to modify its wastewater pretreatment permit to allow for more zinc discharge.
Daily monitoring reports The Dispatch obtained from MDEQ’s offices in Jackson last week show the plant is currently discharging more zinc effluent into its wastewater system than its permit allows.
Yokohama’s permit, issued in June 2014, more than a year before its West Point operations began, allows a daily maximum of 1.066 milligrams per-liter of zinc effluent. The company and MDEQ agreed on that amount when the permit was issued, said Harry Wilson, chief of the environmental permits division for MDEQ.
The company exceeded that limit in August and September 2015 right as production started. It proceeded to come in under the limit the following four months.
According to MDEQ documents, the state corresponded with Yokohama on Sept. 15, 2016, notifying the company that it had exceeded the limit again in February, May, June and July of 2016.
The company’s zinc levels deviated compliance by 30 percent in February, 61 percent in May, .4 percent in June and 93 percent in July 2016.
“We’re currently trying to resolve any issues there may be at this time,” said Cornell Nelson, environmental health and safety manager for Yokohama Mississippi.
He declined to comment further.
Yokohama’s corrective measures
According to MDEQ and Yokohama correspondence, the zinc levels for the West Point plant were determined based on the permit for the company’s manufacturing plant in Virginia.
Now that production is underway in Mississippi, Yokohama’s letter to MDEQ states “it is apparent that the wastewater discharge volume and characteristics differ from the (Virginia) facility and a modification of the (Mississippi) permit is necessary to represent the actual operation of the (Mississippi) facility.”
Wilson said the company is working with the city of West Point to determine an acceptable level of zinc based on the actual discharge flow rates, and the permit should be modified to meet compliance soon.
Not a health hazard
Even at these discharge levels, both Wilson and West Point’s chief operator for wastewater Keith Fortenberry said the zinc poses no danger to the drinking water in the city system.
MDEQ regulates wastewater so streams, creeks and rivers are swimmable and fishable, Wilson said. So, ingestion of that water would result from eating fish or accidental swallowing while enjoying water activities, not from drinking water from a faucet.
But Yokohama’s wastewater goes through a series of processes before it ever reaches those waterways.
“The City of West Point is in compliance with water quality standards,” Wilson said.
Fortenberry said Yokohama’s wastewater is combined with wastewater from other customers and is processed through two city-owned pumping stations before going to its treatment plant, which means Yokohama’s high levels of zinc are diluted well below compliance by the time the water is discharged into waterways.
That dilution also prevents the city’s wastewater system from being overwhelmed by certain elements that could damage the system and cost a substantial amount of money to repair, Fortenberry said.
“If it was something that could be harmful, DEQ would contact us,” he said.
Past issues with cadmium permit
Before Yokohama even began operations in West Point, an MDEQ permitting error raised questions about the company’s output of cadmium in its wastewater.
The Dispatch reported in June 2015 that MDEQ had permitted Yokohama to discharge .04 milligrams per-liter of cadmium, twice the amount West Point city ordinance allowed in its wastewater treatment system.
But according to MDEQ records, the tire manufacturing hasn’t discharged any cadmium into its wastewater since local operations began.
Cadmium, a known cancer-causing agent, 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.
Like the zinc limit, the cadmium limit originated from the Virginia plant, where a level of .04 milligrams of cadmium per-liter was deemed safe, according to Carla Brown, the MDEQ engineer who wrote the permit.
After a story published in The Dispatch, the permit was changed to city ordinance specifications, which sets the limit at .027 milligrams per-liter.
You can help your community
Quality, in-depth journalism is essential to a healthy community. The Dispatch brings you the most complete reporting and insightful commentary in the Golden Triangle, but we need your help to continue our efforts. In the past week, our reporters have posted 41 articles to cdispatch.com. Please consider subscribing to our website for only $2.30 per week to help support local journalism and our community.