Chairing the Senate chamber at the time, Massachusetts Democrat Elizabeth Warren announced shortly before 6:30 pm ET that the Senate's bill approving the Keystone XL Pipeline had failed 59-41.
The bill needed a 60-vote supermajority to be sent to President Obama's desk.
The House version of the bill was sponsored by Rep. Bill Cassidy (R-La.), and the failed Senate version was sponsored by embattled Sen. Mary Landrieu (D-La.), who faces a runoff election with Cassidy in December for her Senate seat.
This is a developing story.