By CBSLA Staff

LOS ANGELES (CBSLA/AP) — The U.S. Postal Service has warned California and 45 states and the District of Columbia it cannot guarantee all ballots cast by mail for the November election will arrive in time to be counted, according to reports Friday.

The warning letters sent to states and obtained by the Washington Post raise the possibility that tens of millions of Americans eligible for mail-in ballots this fall will not be able to use them — even if they follow election rules.

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In a letter dated July 31 addressed to Secretary of State Alex Padilla, Executive VP & General Counsel at United States Postal Service Thomas Marshall wrote that some of California state requirements “appear to be incompatible with the Postal Service’s delivery standards”.

Marshall also warned that since the state allows new voters to register as late as 7 days prior to Election Day, there is “significant risk that the ballot will not reach the voter before” then, meaning the voter would not be able to cast that ballot.

Officials in California, Michigan, Oregon, Virginia, Iowa, Ohio, Indiana, Pennsylvania, Utah and New York all confirmed to The Associated Press that they had received the Postal Service letters of warning.

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Postal workers say in addition to ongoing service disruptions due to COVID-19, they’re having to adjust to cost-cutting measures put in place by its new postmaster general.

“There’s quite a bit of concern regarding the congestion, the stockpiling of mail, we have mail piled into trailers,” said Omar Gonzalez of the American Postal Workers Union. “Trucks leave the processing plant to the delivery units are not always full. Not always with a full load of mail. And then will call at the regional units is delayed so it’s compounding and compounding.”

In a statement to CBSLA, the USPS said they are using all available resources to match the workload created by the pandemic, and that they appreciate the patience of their customers and the efforts of employees as conditions continue to change.

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(Copyright 2020 CBS Corp. The Associated Press contributed to this report.)