The Minnesota Department of Health is conducting a survey to locate people who may have been exposed to asbestos-tainted vermiculite in northeast Minneapolis. The search is focusing on people who lived near the W.R. Grace plant that shut down twelve years ago. Grace used vermiculite to manufacture attic insulation. The company disposed of heaps of excess vermiculite by posting a sign offering "free crushed rock." Many nearby residents carried off the pellets to fill their gardens. The Health Department wants to warn people about the possibility of asbestos-related illnesses showing up ten to forty years after exposure. Epidemiologist Jean Small Johnson works for the department and says they plan to contact six thousand residents, but the challenge will be finding people who have since moved away.