An Engineer Combat Battalion (ECB) was a designation for a battalion-strength combat engineering unit in the U.S. Army, most prevalent during World War II. They are a component of the United States Army Corps of Engineers. Also known as "Combat Engineer Battalions", they were typically divided into four companies: A, B, C, and Headquarters and Service (H&S). In the Pacific Theater the U S Army 42nd Combat Engineers took part in the hard-fought high casualty Battle of Attu Aleutian Islands (1943) and the Battle of Manila, Luzon Philippines (1945), earning 2 Battle Stars.