The Environmental Protection Agency issued final rules for the removal or sealing-in of cancer-causing asbestos in the nation's elementary and secondary schools at a cost officials estimated at about $3.1 billion. The new rules call for the inspection of all schools by "accredited inspectors" and for the submission of asbestos "management plans" to state governors by Oct. 12, 1988. But the EPA pleaded with schools to start asbestos inspections now, warning that they cannot meet the deadline if too many wait until summer vacation. Waiting to comply with the rules will cause the work to be too much for trained inspectors and asbestos program writers to handle, the agency warned. Inspections must cover asbestos that would be safe if undisturbed, such as tiles, in addition to the dangerous variety that can throw off breathable fibers.