JOHANNESBURG (AP) — Royal Dutch Shell's Nigeria subsidiary "fiercely opposed" environmental testing and is concealing data showing thousands of Nigerians are exposed to health hazards from a stalled cleanup of the worst oil spills in the West African nation's history, according to a German geologist contracted by the Dutch-British multinational. The cleanup halted 17 months ago was part of a British out-of-court settlement in which Shell paid $83.5 million to 15,600 fishermen and farmers for damages from two oil spills caused by old pipelines in 2008 and 2009 that devastated thousands of hectares of mangroves and creeks. Holtzmann's letter warns that children bathing in creeks are in danger of harm from toxic substances, as are people who drink from hand-dug wells. Shell has a responsibility to share this information with the community to ensure they can take steps to protect themselves and their children, a statement from the rights group said.