You can find a wealth of material from government agencies by focusing your Google searches on specific U.S. government domain names (.gov or .mil)
click the links for sample results
Examples: BP oil spill site:gov (searches government sites for terms)
delphinidae dolphins site:epa.gov (search within an agency www site)
marine mammals site:www.nmfs.noaa.gov (a specific file server)
hypoxia Gulf of Mexico site:gov filetype:pdf (searches government sites for material in pdf format)
geothermal energy site:energy.gov
IED injuries site:mil
terrorism site:dtic.mil
