A truck bearing 42 barrels of radioactive waste from the Idaho National Engineering and Environmental Laboratory hit the road yesterday, the first shipment from outside New Mexico to head to the recently opened Waste Isolation Pilot Plant near Carlsbad, N.M. About 4,900 more shipments from INEEL containing waste generated during production of nuclear weapons will follow over the next 19 years. Environmentalists continue to fight the WIPP project, which they claim could leak and contaminate the Rio Grande and Pecos River.