Yesterday, I blogged about rumors that conservative economist Randall Lutter was headed to the White House Office of Information and Regulatory Affairs.

After a bit more digging, we can now be certain that Lutter is at OIRA. The rulemaking docket for EPA’s recent proposal to tighten the air pollution standard for sulfur dioxide contains at least one email exchange between Lutter and EPA staff. The emails were sent Nov. 23.

Update: The Washington Post has also confirmed that Lutter was working on the SO2 rule, and is saying, "Documents in EPA's public docket show he is now probing whether a rule to cut sulfur dioxide emissions would cost coal-fired utilities too much."

Update: Here is the document referenced in the Post article.