An article by Debra Jopson in the Sydney Morning Herald back in October says:
'A researcher who has found strong evidence that autism is caused by mercury poisoning has been refused access to data that could point to emissions from coal-fired power stations.'
Apparently information on autism by postcode is being withheld by the Department of Families, Housing, Community Services and Indigenous Affairs on privacy grounds.
See 'Autism coal link study stalled by government' by Debra Jopson in The Sydney Morning Herald, Fairfax, October 4, 2010.
Something causes autism.