NOGALES — Officials with the Arizona Department of Environmental Quality are warning local residents that raw sewage is flowing into a tunnel under the international border, which transports stormwater from Nogales, Sonora, to Nogales, Arizona.

The sanitary sewer overflow originates in Nogales, Mexico, and is exiting the tunnel about one mile north of the international border, dumping it into the Nogales Wash, said a news release from the state’s environmental protection agency.

The sewage could reach the Santa Cruz River, depending on the volume and velocity of the flow, the release said.

People are urged to avoid these areas, because of potential health risks to people and animals from exposure to raw sewage.

Untreated sewage carries pathogens that pose a risk to human health and the environment. People and animals that come into contact with untreated sewage are at risk of infection from those pathogens, the agency said.

The U.S. and Mexico sections of the International Boundary Water Commission (IBWC) are in contact with the utility in Nogales, Sonora, to find the cause of this sewage overflow.

The state’s environmental protection agency officials are monitoring the situation. They are in contact with the utility in Nogales, Sonora; the City of Nogales, Arizona and the Santa Cruz County Health Department.

The agency recommends avoiding contact with the water in this area.

Medical treatment should be sought by anyone who believes his or her health has been compromised by the sewage.

Pets and livestock should be prevented from exposure to the sewage. Pets can be especially susceptible because they tend to drink while in the water and lick themselves.

Any contact with the sewage should be reported to the Santa Cruz County Health Department at (520) 375-7900.

The health department recommends anyone in contact with the sewage, through direct contact of inhalation, should contact a physician.