 Further complicating the situation, the Marines' water was distributed in empty oil drums, contaminating the water with the oil residue.Still, by the eighth day the 5th and 7th Marines had accomplished their objectives, holding the airfield and the southern portion of the island, although the airfield remained under threat of sustained Japanese fire from the heights of Umurbrogol Mountain until the end of the battle.American forces put the airfield to use on the third day.