A stench in Southern California began in Mexico when 143 million gallons of sewage leaked into the Tijuana River, according to the findings in a new report. The spill reportedly resulted from a damaged pipe on the Mexican side of the border.

The report, which was released on Friday by the International Boundary and Water Commission (IBWC), sheds light on complaints from residents of a “strong raw sewage odor and cloudy, grey water” in the area around Imperial Beach, San Diego.

Mayor of the city, Serge Dedina, shared the report online, describing it in a Facebook post as “the largest spill of raw sewage into the Tijuana River in at least over a decade and possibly longer.”

An estimated 143 million gallons of sewage are believed to have leaked into the river because of a rupture in a sewage collector pipe near a junction on the Mexican side of the border, according to the report.

It then crossed over the border and drained into the Pacific Ocean just south of San Diego Bay. The spill is estimated to have begun on February 6 but was not reported until February 23.

Residents in the area told the San Diego Reader that the stench was “putrid” and “like ammonia from toilet cleaner in our eyes,” while another local, Crystal Sander, said it was “so bad” she was “heaving from the smell.”

Sewage spill report via #IBWC -stinky conditions caused by 143 million gallon sewage spill into TJ River staring 2/6. pic.twitter.com/ieSwC6dWdK — Serge Dedina (@Serge4IBMayor) February 24, 2017

“What I am worried about is that now with US-Mexico relations at a new low, this could be the new normal – in which our US-Mexico Water Treaty Minute 320, in which sewage spills are supposed to be reported, are covered up,” Dedina wrote on Facebook.

Dedina, who contacted the IBWC after receiving complaints of a stench in the area, criticized officials on both sides of the border for failing to report the spill. “It’s a major communication failure,” he told the San Diego Tribune. “It’s obviously something they knew for a very long time.”

The spill would have resulted in beach closures in the area had they not already been closed due to heavy rain causing sewage run-off.

The IBWC's Lori Kuczmanski has said the Mexican Section of the commission has been asked to investigate their wastewater utility CESPT (Comisión Estatal de Servicios Públicos de Tijuana) in an attempt to “correct the problem."