Urged by fellow Republicans to cooperate with Attorney General Lisa Madigan, a Democrat who isn’t running for re-election, the Rauner-led Illinois Environmental Protection Agency instead refused in late August to provide Madigan’s office with key documents about highly toxic ethylene oxide gas emitted in Willowbrook by Sterigenics, a global sterilization company bought in 2011 by a private equity fund co-founded by Rauner. The governor still has a financial interest in Sterigenics, according to a report he filed in May with a state ethics commission.