Schools are in danger of becoming segregated again as a result of rising Latino isolation in the West and outmoded integration plans in the South, the National School Boards Assn. said. Even now, "The data for segregation of Hispanic students within metropolitan America is grim," an association report said. Heading the list of segregated areas were New York, El Paso, San Antonio, Los Angeles and Chicago. For blacks, the most segregated states were Illinois and New York. "The march to school integration is certainly not over, and school systems are finding no quick and easy solutions," James Oglesby, president-elect of the association, said in releasing a study of desegregation trends from 1968 to 1986. At the national level, the study found black-white integration stable for the past two decades despite efforts to dismantle desegregation plans during the Reagan Administration. At the same time, "Hispanics have been becoming steadily more isolated in virtually all parts of the country," it said.