Lloyd W. Hazleton, 79, founder of Hazleton Laboratories, one of the world's largest biological testing services. Hazleton, who had a doctorate in pharmacology, founded the biotechnology research company in 1946 on the grounds of an old country schoolhouse in Fairfax, Va. The company, originally known as Hazleton Laboratories America Inc., became one of the world's largest testing services, doing pretests of new chemicals for virtually every major chemical, cosmetics and pharmaceutical manufacturer. He sold the company in 1968 and retired as president. The company is now known as the Hazleton Corp. and is based in Herndon, Va. Hazleton had joined the faculty of Georgetown University Medical School as a pharmacology professor in 1939. He left Georgetown two years later and taught at George Washington University until he founded Hazleton Laboratories. In McLean, Va., on Saturday of cancer.