The federal government next week will launch a massive study to see whether workers who helped clean up last year's Gulf of Mexico oil spill are getting sick as a result...The study was commissioned after some cleanup workers reported chest pain, headaches, breathing difficulties and other ailments that they believed were linked to the oil spill, said Dale Sandler...of the National Institute of Environmental Health Sciences...The study, funded with an initial $8 million from the government and $6 million from BP PLC, aims to follow 55,000 former cleanup workers for up to a decade. It will be the biggest study ever of an oil spill's health effects, federal officials said. It will look at everything from skin rashes to breathing problems to potential increased cancer risk...BP didn't design the study and won't help conduct it, government and BP officials said. BP wanted "an independent and credible review" of any potential link between cleanup workers' heath problems and the spill, said Richard Heron, BP's chief medical officer...The study's findings could, indirectly, raise BP's bill for the spill. Lawyers often use epidemiological studies as ammunition in lawsuits contending environmental incidents such as spills injured their clients...The spill study won't prove definitively whether BP oil caused any health problems, said scientists who helped design it.