Minimal amounts of gamma isomer of BHC have remained toxic to the eastern subterranean termite, Reticulitermes flavipes (Kollar), for more than 10 years in sandy soil under the conditions of the tests. Under the same conditions, aldrin, dieldrin and heptachlor have remained toxic in minimal amounts for 7 years of testing. Although chlordane, DDT, TDE, methoxychlor, toxaphene, pentachlorophenol, and sodium pentachlorophenate have remained toxic over the 10-year period, larger amounts of these chemicals were required in the treated soil used in these tests.