In the latest skirmish over transparency at the troubled Oroville Dam, a Northern California activist group has sued state officials alleging they’re illegally withholding information about potentially toxic asbestos. AquAlliance, a Chico-based advocacy group focused on Sacramento Valley water issues, filed a lawsuit in Sacramento Superior Court on Tuesday alleging the Department of Water Resources broke state records laws when it denied the group’s request for emails containing information about the asbestos at the dam. The state did release nine documents, the group said, but not the relevant emails.