reporter: b.p. has 700 temporary clean-up workers on grand isle and thousands throughout the gulf, scraping up tar balls and oil in 90-degree heat for 12 to $20 an hour. many come from private subcontractors who require name, date of birth and social security number for each hire. the data is then turned over to local law enforcement to ensure safety at clean-up sites. but so far, at least three workers have been arrested on outstanding warrants while on the job. narcotics, assault and for child molestation. local law enforcement officers say the current system is a disaster waiting to happen. we re liable to have a situation with a group of people turn into vigilante force and you have a huge wedge where it s up against them. reporter: what is not clear is what percentage of the contractors are already convicts, currently on prison and on work release programs. let out temporarily to clean oil. louisiana department of corrections confirm that dozens of inmates on work