Work has begun to stop a decades-old problem of millions of gallons of sewage from Tijuana, Mexico, flowing into the United States and polluting San Diego County beaches, the Trump administration’s top environmental protection official said Wednesday. For more than 40 years, wastewater from Tijuana’s dilapidated system has spilled across the border and polluted the waters off Imperial Beach, a city of about 30,000 south of San Diego. The pollution has posed health risks to surfers, Border Patrol agents and even Navy SEALs who train near there, officials said.
