I agree with cjsews...wash your remaining yardage and use with dark fabrics on the front.
I also would wash it with either color catchers or white rags that you can later bleach to see if the fabric is continuing to run. If after 3-4 washings it's still running, I'd probably toss it despite it's being that large a piece of fabric. For me, knowing it was still going to be problematic, would make me not want to use it.