City officials in Charlotte, N.C., have reported two unrelated incidents of chemical discharge into local waterways. The incidents occurred within 48 hours of each other, but both posed no immediate risk to local residents.

The first incident happened on Feb. 6, when banned chemical compounds known as PCBs were discharged along with partially treated wastewater from the Mallard Creek sewage treatment plant. However, authorities stated that the spill was contained before the chemicals reached the creek itself.

Just two days later, on Feb. 8, city authorities said that ethanol was illegally discharged and flowed into the Sugar Creek Wastewater Treatment Plant. The discharge was discovered when employees at the plant noticed a strange odor coming from the wastewater. The plant was temporarily shut down and flow was diverted to an isolated basin at the facility.

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After sampling the discharge, officials announced that no traces of PCBs were found and the two spills were not related. They noted that ethanol was typical of a fuel spill, the Charlotte Observer reported.

Authorities stated that there was no public health risk associated with the incidents and tap water was safe for washing, bathing, cooking and drinking. However, local residents are advised to avoid human and animal contact with water from Little Sugar Creek, Mallard Creek and the Rocky River in Cabarrus County, the news source reported.