Part of the Federal Penitentiary at Lompoc is in a permanent “lock-down” status because of 184 Cubans who face no criminal charges but could spend the rest of their lives in prison. The men are called Marielitos because they came to the United States in the so-called Mariel boat lifts of 1980 and are being held by the Immigration and Naturalization Service because of possible criminal histories. The prison has tight security because of prison riots staged by Cuban inmates in Atlanta and Oakdale, La. “No one likes to run a lock-down prison,” said Warden Richard Rison. “But they’ve already demonstrated they can be explosive. When they arrived, we didn’t know if we’d gotten the ones who had burned buildings or the ones standing on the side.” The Marielitos are locked in their cells for 23 hours a day and often rebel by screaming, throwing food or drumming on cell walls and bars.