Use 1Search from the library's home page to search for books in the Valley Library, OSU branch libraries, and Summit Libraries.
Environmental and Molecular Toxicology materials generally fall into the in R call number range and are located on the 1st floor of The Valley Library. This is a highly interdisciplinary discipline, however, so you will find books in many other areas as well including Qs and Ss (also on the 1st floor).