I have been talking with the authors of two studies of immigrant workers engaged in the Katrina cleanup. There are an estimated 10,000 immigrant workers of whom half may be undocumented. Both researchers report that very, very few of their work injuries are handled through the workers comp system. Instead, free care is used. This is a very serious problem. I expect to write more on it as more information becomes available. I have already posted on the published study done by Tulane and UC Berkeley researchers.