On Wednesday, internal emails revealed that the CDC changed its school mask guidelines in response to threats from a prominent teachers union.

According to Fox News, emails reveal that the National Education Association, America's largest teachers union, "sent a draft statement to White House officials that included harsh criticism of the Centers for Disease Control and Prevention's masking guidance."

The teachers union published a toned down version in the end, with the CDC changing its tune on masking in schools to masks for all, regardless of vaccination status.

Watchdog group Americans for Public Trust released these emails to Fox News after obtaining them through a Freedom of Information Act request .

"The new emails show further coordination between the White House and teachers unions just months after reports highlighted the extent the unions had influenced the administration's messaging on school reopenings," wrote Fox News.

Communications between the NEA and Biden Administration officials regarding masks began on May 13, the day the CDC announced that fully vaccinated Americans no longer need to wear masks both outdoors and inside, creating confusion on how the policy change would apply in the upcoming school year.

On May 14, White House director of labor engagement Erika Dinkel-Smith aid said that she stopped the NEA from releasing a critical statement that had called for immediate clarification from the CDC.

"Would you know when Dr. Walensky would be able to call NEA-Pres. Becky Pringle?" Dinkel-Smith wrote in that email. "They've gotten significant incoming and are getting targeted for a response from the media. I've gotten them to hold on their statement calling for clarification."

Dinkel-Smith received the draft of the NEA's critical statement that same day.

"We appreciate the developing nature of the science and its implications for guidance, but releasing the guidance without accompanying school-related updates creates confusion and fuels the internal politicization of this basic health and safety issue," the emailed draft statement read. "CDC has consistently said, and studies support, that mitigation measures, including to protect the most vulnerable, remain necessary in schools and institutions of higher education – particularly because no elementary or middle school students, and few high school students, have been vaccinated."

"This will also make it hard for school boards and leaders of institutions of higher education to do the right thing by maintaining mitigation measures," the statement continued. "We need CDC clarification right away."

Following the release of the updated CDC mask guidance, as well as discussions and coordination with the Biden Administration, the NEA released a toned down version of the draft statement.

The emails also revealed lines of communication between union leadership and the White House and CDC.

"On May 14, Dinkel-Smith asked CDC chief of staff Sherri Berger to connect NEA President Becky Pringle with the CDC director. Berger responded to the request by writing 'will do' and that the CDC director was 'connecting w/ Becky now,'" wrote Fox News.

30 minutes following that email exchange, Berger wrote that she had spoken with Pringle and President of the American Federation of Teachers Randi Weingarten.

The CDC officially updated its school mask guidance the following day, on May 15, to reflect that all people in schools should wear masks regardless of vaccination status.

"This batch of emails came just weeks after we already exposed the teachers unions influenced the CDC on school openings," Americans for Public Trust Executive Director Caitlin Sutherland told Fox News. "Lo and behold, less than two weeks later, they're at it again, but this time in relation to mask guidance."

Those emails were dated just days before the union was revealed to have a large part in creating the language for the CDC's for school reopening this fall.

In a press briefing on February 12, the CDC admitted that it was not only science that they used as their guide, but "...an understanding of the lived experiences, challenges, and perspectives, of teachers and school staff, parents, and students."

The CDC had reportedly asked the American Federation of Teachers (ATF) for "language" to include in their school reopening recommendations, to which the ATF obliged.

When asked by C-SPAN's Washington Journal about the language from the unions that "ended up nearly verbatim" in CDC recommendations, Weingarten said "They asked us for language and we gave them language when they asked for it."