SAN DIEGO (FOX 5/KUSI) -- The Tijuana River Valley is known for its severe pollution, with toxic water and air posing significant health risks to the local community.

County supervisors are urging the federal government and the EPA to designate the Tijuana River Valley as an EPA SuperFund cleanup site, following previous rejections of their pleas.

Over the past few years, efforts have been made on both sides of the border to improve sewage treatment plants, which has gradually reduced the amount of sewage being dumped in the area.

Despite these improvements, the full extent of land toxicity remains unknown, as there has not been a recent study to determine the danger posed by decades of toxic waste.

County supervisors are now appealing to the state water board to conduct research on th

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