New York--Bethlehem Steel, the No.3 U.S. steel maker, Monday filed for Chapter 11 bankruptcy protection amid one of the worst markets for steel companies in years. The Bethlehem, Pa.-based company listed $4.2 billion of assets and $4.5 billion in debt in its filing with the U.S Bankruptcy Court for the Southern District of New York. The steel industry has been suffering for three years from sluggish demand in the down economy, depressed prices and a glut of supply. Analysts predict that more steel companies will be forced to file for bankruptcy in the deteriorating economic climate. A merger partner or buyer is a possibility for Bethlehem, according to Jeffrey Tanenbaum, an attorney for the company.