This report is the third of a series of reports based on data collected in the 1978 National Sample of Scientists and Engineers survey. Profiled are the characteristics of 29,775 persons represented in the national sample's field of environmental scientists: 24,615 earth scientists, 3,481 atmospheric scientists, and 1,678 oceanographers. Characteristics are discussed under five headings: (1) composition (sex, age, regional/racial distribution); (2) education and training; (3) professional experience and growth of field, focusing on years of professional experience, field of science/engineering in 1976, and job mobility in 1978; (4) labor force participation; and (5) income, focusing on basic annual salary rate of full-time employed environmental scientists in 1978. Text material is supplemented by statistical data presented in three text tables, one chart, and individual tables related to each of the five areas. Survey methodology (including questionnaire used and response rates) is provided in five appendices. Findings, among others, indicate a predominantly male (96 percent), white (98 percent) sample with a median age of 47 years. In addition, 93 percent were in the labor force, and of those not in the labor force, 86 percent were retired. The 1978 basic salary rate of full-time employees was $30,234. (JN)