WILMINGTON — In an apparent mixup of gas canisters, the Cape Fear Public Utility Authority accidentally introduced sulfur dioxide into the Monterey Heights water system causing complaints of foul-smelling water by customers.
The Monterey Heights system provides water to an area south of Monkey Junction.
“The odor is believed to have been caused by the introduction of sulfur dioxide, a gas commonly used in food processing and preservation, into one well in the system. The concentrations that resulted in the drinking water were below those found or allowed by regulators in many foods,” according to a CFPUA press release.
So how exactly did this happen?
“The sulfur dioxide was in a gas cylinder supplied to CFPUA as part of an order for chlorine. CFPUA is looking into why the incorrect chemical was supplied and how a similar incident may be prevented in the future,” according to the release.
For about 10 hours on and off the tank pumped the gas into the water system on Saturday and Sunday — staff started looking into the situation when a sensor went off alerting them to the fact no chlorine had been added to the water.
“Chlorine is added to disinfect and reduce odors that occur naturally in water pumped from Monterey Heights system wells. About a half-dozen customers served by the Monterey Heights system called CFPUA on Sunday evening to report a sulfur smell in their drinking water,” according to the release.
CFPUA has been flushing the system and is monitoring chlorine levels, as far as the human safety concerns with sulfur dioxide, CFPUA says the main concern with it is inhalation.
“Sulfur dioxide is a gas, so information about potential health effects are chiefly focused on inhalation. Sulfur dioxide is found in foods such as wine and some dried fruits. The Food and Drug Administration considers 10 parts per million or less of sulfur dioxide to be an ‘insignificant amount’ in food. Federal regulators allow a total concentration of sulfur dioxide in wine as high as 350 parts per million, according to the release.
Based on estimates of the amount of sulfur dioxide added and the volume of water distributed from the well, along with the dilution that would have occurred as that water mixed with that from other wells, the concentrations of sulfur dioxide in drinking water was calculated to be less than 5 parts per million, a concentration significantly less than those levels cited in food regulation. CFPUA is consulting with the N.C. Department of Environmental Quality and New Hanover County Public Health as part of its review of the incident,” the release concludes.