Employee states as he was crawling across a catwalk, he bumped his head on an I-Beam and knocked his hard-hat off onto the catwalk. He turned to pick up the hard-hat, and before putting it on, he turned back and hit his head on the I-Beam, sustaining a laceration that required stitches. He was on light duty for two days and returned to full duty on 5/18/2011.