Hillary Clinton sounded off on Twitter on Tuesday, warning President Trump's executive order to undo his predecessor's rule on carbon emissions puts "American lives at risk."

She retweeted a tweet from NextGen Climate, which cites statistics from the Obama White House and EPA on the benefits the Clean Power Plan, if fully implemented.

"Trump's attempts to kill the #CleanPowerPlan are a threat to our health, our jobs, and our future," NextGen Climate said in its tweet.

In retweeting NextGen Climate, Clinton said that these are "more than statistics, they're American lives at risk because this administration willfully ignores the science."

This wasn't the first time Clinton got political on Tuesday.

Earlier in the day she appeared at an event in California, where she lamented the lack of women in Trump's administration and also took aim at White House press secretary Sean Spicer and Fox News' Bill O'Reilly.