SAN DIEGO (Border Report) -- The County of San Diego is trying to get the Environmental Protection Agency to reconsider its decision to deny financial and other support to clean up the Tijuana River Valley. The EPA is refusing to designate the valley as a "superfund site," which would clear the way for the agency to step in. In the past, the designation has been used to clean up environmental disasters and hazardous spills across the country. The EPA relied on studies done by federal agencies such as U.S. Customs and Border Protection and the International Boundary and Water Commission to arrive at its decision. Boulders installed in Tijuana River to keep toxins, sewage from splashing into the air In a letter to the County of San Diego, the EPA's Michael Montgomery wrote that "none of the contaminants exceeded EPA’s regional screening levels for human health in residential soil ... the risk posed by the Tijuana River Valley isn’t high enough." San Diego County Supervisors Jim Desmond and Terra Lawson-Remer questioned the EPA's decision not to designate the Tijuana River Valley as a "superfund site." (Aaron Eudalay/KSWB) But according to Supervisor Terra Lawson-Remer, the soil samples used by the EPA were taken six years ago and are outdated. "It's troubling that the EPA didn't even visit the site and instead based its decision on samples collected years ago -- the reality is that things have gotten much worse since then," she said. "Absence of evidence is not evidence of absence." Lawson-Remer, who is the acting chair for the San Diego County Board of Supervisors, led a unanimous vote by her counterparts to ask the EPA to reconsider. "With hazardous waste closing beaches for over 1,000 days, a record number of air pollution complaints being filed by residents, and the CDC now getting involved, my question is: How much sicker do San Diegans need to get before this is treated as a crisis that is so obviously is?" Leaders lament Biden’s refusal to declare emergency for polluted Tijuana River Valley Montgomery said during Wednesday's board meeting that the EPA is willing to work with the county and that it's already involved with several county agencies in an ongoing effort to determine the amount of pollution in the valley. He also stated one of the reasons the EPA did not label the Tijuana River Valley as a "super fund site" is that there are already several projects in the works to clean up the area such as the renovation of the International Wastewater Treatment Plant, which will double its capacity to treat wastewater that comes in from Mexico. Visit the BorderReport.com homepage for the latest exclusive stories and breaking news about issues along the U.S.-Mexico border But San Diego County supervisors say this project won't come online for at least five years and insists the EPA step up now to clean up the valley.