Montana Senator Sends Stern Letter To Mexican Pres.

Montana's newest senator recently sent a letter to Mexican President Claudia Sheinbaum over the dumping of waste into waters that end up in areas where U.S. servicemen train.

Republican U.S. Senator from Montana Tim Sheehy demanded that her government act now to stop the flow of poisonous, untreated sewage across the Mexican border into waters where American servicemen train.

Over 100 billion gallons of raw sewage, garbage, and rainfall have been dumped from Tijuana to San Diego since 2018, sickening thousands of Americans, including Navy SEALs and Marine special forces who train in the impacted seas.

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View the full text of Sheehy's letter below:

Dear President Sheinbaum,

I am writing to demand that Mexico immediately stop dumping millions of gallons of raw sewage into the Pacific Ocean every single day. For decades, this toxic tide has been flowing across the border and into the waters where our Navy SEALs train, dating back to my own time as a SEAL. It is sickening our troops and directly harming America’s military readiness.

As you know, Tijuana has experienced a significant population surge—largely driven by illegal migration toward the United States—and as a result, the city’s aging wastewater system has been overwhelmed. In fact, since 2018, more than 100 billion gallons of raw sewage, trash, and stormwater has flowed from Tijuana to San Diego.

This continuous discharge is sickening thousands of Americans annually, including U.S. Navy SEALs and Marine special forces who train in the affected waters. In February 2025, the Department of Defense Office of Inspector General concluded that, absent action, Navy Special Warfare Command would be advised to cancel or relocate up to 75 percent of water training exercises at Naval Amphibious Base Coronado due to elevated bacterial contamination levels. This poses an unacceptable choice between preserving the health of our service members and maintaining essential military readiness—both of which are critical to our national security.

As part of the 2020 United States-Mexico-Canada Agreement, Congress authorized $300 million for the International Boundary and Water Commission (IBWC) to address this ongoing crisis. However, during the engineering and planning process, it was determined that the treatment plant would require significant remediation before the planned expansion could move forward. Since then, Congress has appropriated more than $300 million in additional funding to complete upgrades at the facility. America is doing its part. It is time for Mexico to do the same.

It is in the interest of both Mexico and the United States to have strong national security ties so we can continue to be regional partners in combating transnational crime. I appreciate your attention to this urgent matter and look forward to your response.

Sincerely,

Tim Sheehy

U.S. Senator