More than 20 people were sickened by contaminated oysters from Maryland after heavy rain caused 25,000 gallons of raw sewage to flow into a Potomac River tributary with no warning from state officials.

According to the Baltimore Sun, from Oct. 28 to Oct. 30, raw sewage flowed into the river, and the St. Mary’s County Metropolitan Commission failed to warn residents of the possible contamination to shellfish and oysters.

However, the Commission did warn residents of the overflow in a Facebook post but made no mention of the dangers of consuming the sewage-infested seafood, the Baltimore Sun said. The incident was also reported to the Maryland Department of Environment.

It was not until Nov. 13, after the tainted oysters were served at a winery event in northern Virginia, that the Commission warned about the contamination after reports of people falling ill after consuming them, the Associated Press reported.

Following the public notice, shellfish harvesting was halted in parts of the river that had the contamination, according to the news outlet.

Maryland Department of Environment spokesperson Jay Apperson told the Baltimore Sun that by then the oysters had been sold and eaten, with more than 20 people sickened, according to a health official in Loudon County, Virginia.

Potomac Riverkeeper Dean Naujoks told the news outlet the failure to notify the public by the Commission was “inexcusable.”

“People are sick because MDE failed to do its job,” he added.

In a statement to The Hill, Apperson said, “To our knowledge, this is the first time something of this nature has happened. We are now working on improving our coordination within programs, through retraining and building redundancies into our process as a safeguard to prevent this from happening in the future.”

oysters Oysters shown opened during the Bluff Oyster & Food Festival on May 26, 2018, in Bluff, New Zealand. Photo: Dianne Manson/Getty Images