CNN was told by the state that it has been adding HaloSan to the water in Denmark since 2008.
An EPA spokesperson tells CNN that HaloSan is not approved to be used to treat drinking water.
Wright tells CNN that he defers to South Carolina’s DHEC.
The state Department of Health and Environmental Control says it required daily monitoring, "performed by the certified system operator," of "any chemical" added to the drinking water, ensuring that the maximum dosage is not exceeded.
But, the couple says there have been concerns about skin rashes and kidney problems among residents for years, although a link has not been made directly to the water.
South Carolina’s DHEC tested Brown and Smith’s home in 2010, and found about twice the legal level of lead in the water.
But Edwards says he couldn’t let go of a nagging feeling that there was something missing, especially after finding red flags, like a 2010 local newspaper story where a city official declared the water had safe lead levels nine days before the testing was conducted.
Wright, Denmark’s mayor, later told CNN that officials were relying on 3-year-old data when talking to the newspaper because that was what was available at the time.
Skeptical of the town’s transparency, Edwards decided to request to test the town’s water at its source — the drinking water wells — for certain bacteria that might be causing some of the rashes and illness that residents described.
Denmark’s mayor told CNN he believes he has done everything to make sure the water is safe.