A coalition of 350 environmental groups will rally Monday to urge Sen. Robert Casey, (D., Pa.) to vote against an upcoming bill on the Keystone XL pipeline.

Representatives of the groups, including Penn Environment, Clean Water Action, and the Sierra Club, say the pipeline would be an environmental disaster. It would carry more than 830,000 barrels per day of oil from Alberta, Canada, to the U.S. Gulf Coast, "affecting not only local ecosystems but the Earth's climate when its output is ultimately burned as fuel."

Casey will be a crucial swing vote, the groups say, in the fight over the pipeline. The U.S. Senate is expected to hold a binding vote this week that would force approval of the pipeline, bypassing the Obama administration.

"The first Keystone pipeline leaked 13 times in its first year alone," the groups said in a news release. "A leak from the XL pipeline would be a BP-size disaster and wouldn't benefit the U.S. in terms of fuel, jobs, or gas prices."

The rally will be held at 12:30 pm. at 2000 Market St.