House Democrats blocked a bipartisan proposal to include unborn children under the Environmental Protection Agency's definition of "vulnerable populations."

The Democrat-controlled House voted 219 to 187 against approving the measure, which would have amended legislation designating a cancer-linked chemical as a hazardous substance. Democrats were responsible for all 219 votes against the language, though four Democrats broke ranks and voted with Republicans to support the inclusion of unborn children in the bill.

Rep. Cathy McMorris Rodgers (R., Wash.) introduced the measure using a procedural tool that allows the minority party to propose an amendment to a bill. The motion added the language, "including any unborn child," to a section of the bill describing "potentially vulnerable populations living near likely destruction or disposal sites." McMorris Rodgers said it helped protect "all Americans" from exposure to toxic chemicals and inform pregnant women about risks to the health of their babies.

"This amendment is a good faith effort to improve this legislation in a way that enhances its effort to protect all Americans from harmful chemicals," McMorris Rodgers said. "When it comes to pregnant women who are at risk, there are two people at risk: the pregnant woman and the unborn child."

Friday's vote comes as House Republicans petition House Speaker Nancy Pelosi (D., Calif.) to hold a floor vote on the Born Alive Abortion Survivors Protection Act, which would require doctors to provide life-saving care to babies who survive abortions. Senate Democrats, including 2020 presidential hopefuls Sens. Elizabeth Warren (D., Mass.), Bernie Sanders (I., Vt.), Amy Klobuchar (D., Minn.), and Cory Booker (D., N.J.), voted to block such care.

McMorris Rodgers said the threat of potentially harmful chemicals extends to the womb, regardless of pro-abortion rhetoric.

"This motion to recommit is simple, it's clear, it's direct. It clarifies the protection of vulnerable populations must include any unborn child," McMorris Rodgers said.

BREAKING: Democrats JUST blocked us from protecting unborn children from hazardous chemicals that harm development. RT to tell them to stop denying the science that the development of a child starts in the womb. #prolife pic.twitter.com/G2a3q06uIN — CathyMcMorrisRodgers (@cathymcmorris) January 10, 2020

Reps. Dan Lipinski (D., Ill.), Ben McAdams (D., Utah), Henry Cuellar (D., Texas), and Collin Peterson (D., Minn.) voted in favor of the measure. Lipinski and Cuellar are both facing significant primary challenges from further left candidates backed by Justice Democrats, the super PAC that is working to defeat moderate Democrats in Democratic primaries.

After defeating the amendment, the House eventually passed the legislation 247-159. The chemicals the legislation takes aim at are considered "forever chemicals" due to the extensive amount of time they take to degrade in the environment.