White out conditions are being blamed for a 20 car pile-up along Interstate 80 in Mercer County. A 59 year old Youngstown Ohio woman was killed in the pile-up. 4 others were injured. The accident happened around 11:30 this morning about 3 miles from the Ohio border. State police said traffic came to a halt in the eastbound lane when visibility turned to zero and cars and trucks began to pile into each other.