Abstract: A horizontally elongate floating boom for confining contaminate material floating on the surface of a body of water. There is a flotation section having a substantially vertical contaminate impervious skirt section extending downwardly therefrom. The skirt section has first and second ends which are adapted to overlap one another. A substantially vertical net section extends downwardly from the skirt section, and has a ballast section attached along a lower edge thereof. Apparatus is provided for securing a first end of a skirt section and a second end of a skirt section together when they are overlapped. In a first embodiment, the ballast section is adapted to rest on the floor of the body of water so as to maintain the boom in a fixed position. In a second embodiment, apparatus is provided for contracting the boom about a portion of the body of water which is encircled by the boom.