NOVELTY - Controlling arthropod comprises providing purified hydrogen peroxide gas (PHPG) to prepare PHPG-containing environment having PHPG final concentration of greater than or equal to 0.05 ppm and maintaining PHPG-containing environment for certain time.    USE - Method for controlling arthropod including Insecta; Arachnida; Diplopoda (e.g. millipede); Chilopoda (e.g. centipede); Collembola (e.g. spring tails); Thysanura (e.g. silverfish, firebrats, bristletails); Ephemeroptera (e.g. mayflies); Odonata (e.g. dragonflies, damselflies); Phasmida (e.g. walking sticks); Orthoptera (e.g. crickets, katydids, grasshoppers); Mantodea (e.g. praying mantis); Blattaria (e.g. cockroaches); Isoptera (e.g. termites); Dermaptera (e.g. earwigs); Plecoptera (e.g. stonefly); Psocoptera (e.g. psocids, barklice); Phthiraptera (e.g. lice including Mallophaga and Anoplura); Hemiptera (e.g. true bugs, waterbug, chinch bug, Reduviidae, stink bugs); Homoptera (e.g. aphids, cicadas); Thysanoptera (e.g. thrips); Neuroptera (e.g. doodle bugs, antlions, lacewings); Coleoptera (e.g. beetles, weevils); Mecoptera (e.g. scorpionflies); Siphonaptera (e.g. fleas); Diptera (e.g. flies, mosquitos, midges); Trichoptera (e.g. caddisflies); Lepidoptera (e.g. bollworm, armyworms, cutworms, codling moth, clothes moth and cabbageworm including immature forms of caterpillars); Hymenoptera (e.g. ants, bees, wasps, hornets, yellow jackets, sawflies); Scorpionida (e.g. scorpions); Uropygi (e.g. vinegaroon); Araneae (e.g. spiders, tarantula); Isopoda (e.g. sow bug, pill bugs, scud); Opiliones (e.g. harvest bugs, daddy longlegs); or palmetto bug, Florida woods cockroach, bed bug, mud dauber, gypsy moth larvae or adult, Japanese beetle, carpet beetle, leafhopper, red spider mite, webworm, whitefly, non-biting gnat, pillbug, boxelder bug, fruit fly, gnat, ground beetle, and ticks, including eggs and larval forms; particularly controlling arthropods in greenhouse, food processing facility including restaurant, food distribution center, food packaging plant, rendering plant, abattoir, fish cannery and grocery store, and/or in agricultural product including fruits, vegetables, nuts, meat and live animal during shipping (all claimed); and repelling insects.    ADVANTAGE - The method reduces arthropod population by greater than or equal to 25%, preferably greater than 95%. Continued use of PHPG prevents reinfestation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) termite control by treating termite-infested house with PHPG;    (2) treatment of houseplant by placing arthropod-infested plant in PHPG-containing environment; and    (3) treatment of animals by placing domestic pet (e.g. cat, dog, or rodent) infested with ticks, fleas, or lice in PHPG-containing environment for certain time; or placing livestock animal (e.g. cattle, sheep, pigs, chicken, or geese) infested with chewing lice such sheep biting lice, chicken body lice, or common hen lice in PHPG-containing environment for certain time.