A failed wastewater pipe in Pueblo, Colorado, released approximately 4.25 million gallons of untreated sewage into the Arkansas River, prompting state officials to warn downstream communities, agricultural producers and recreational users to avoid contact with the water.

Pueblo utility officials said a sewage pipe repaired with concrete inside a stormwater discharge pipe failed under pressure Wednesday. The release was discovered and stopped Thursday, but the sewage had already entered the stormwater system and discharged into the Arkansas River east of Interstate 25.

Water samples collected by Pueblo County health officials showed low E. coli levels upstream of the release but “extremely high” levels downstream, according to the Colorado Department of Public Health and Environment (CDPHE). State officials advised against using or recreating in the river until testing indicates bacteria levels have returned to normal. Pets and livestock are also being advised to stay out of the affected water.

The Colorado departments of health and agriculture are working with farmers and ranchers in the Lower Arkansas Valley to assess potential impacts to agricultural water supplies. Growers using river water have been advised to test their water and identify alternative sources where necessary.

Officials said there is currently no evidence that the spill has affected downstream public drinking water systems. Those systems were notified of the incident and were able to shut off intakes if necessary.

The spill could pose additional challenges for agricultural operations because of ongoing drought and low river flows, which can limit the natural dilution of contaminants. Pueblo’s Wastewater Department issued a water-contact warning through Aug. 31 for downstream communities including Avondale, Boone, Fowler, Manzanola, Rocky Ford, Swink, La Junta and Las Animas.