Attorneys for Don Blankenship say they have conducted a survey that shows former Massey Energy CEO cannot get fair trial in southern West Virginia.
Blankenship was charged with conspiring to violate safety standards at Upper Big Branch Mine after a blast killed 29 men in 2010. It was the deadliest U.S. mine disaster in four decades.
In a memorandum filed in federal court, Blankenship's attorneys say the results of a "reliable survey" show that about half of the potential jurors in the Beckley Division already believe Blankenship is guilty.
The memo was made publicly available Wednesday after the AP and other media challenged its sealing.
Blankenship's attorneys want the case moved to Martinsburg or Baltimore.
Prosecutors favor Charleston or Huntington if relocation is necessary.