Prosecutors call ex-coal CEO's misdemeanor conviction historic, but it was less than hoped for

Don Blankenship smiles as he leaves the federal courthouse after the verdict in his trial in Charleston, W.Va., Thursday Dec. 3, 2015. The former Massey Energy CEO was convicted Thursday of a misdemeanor count connected to a deadly coal mine explosion and acquitted of more serious charges. A federal jury in West Virginia convicted Blankenship of conspiring to willfully violate mine safety standards. The misdemeanor charge carries up to one year in prison. He was acquitted of a more serious conspiracy charge that could have netted five years in prison. He was also acquitted of making false statements and securities fraud. (F. Brian Ferguson/Charleston Gazette via AP) MANDATORY CREDIT (The Associated Press)

FILE -In this Tuesday, Dec. 1, 2015, file photo, Former Massey Energy CEO Don Blankenship makes his way out of the Robert C. Byrd U.S. Courthouse during a break in deliberations, Charleston, W.Va. Jurors have resumed deliberations in ex-Massey Energy CEO Don Blankenship's trial. Thursday, Dec. 3, 2015. Jurors have said twice they couldn't agree on a verdict. They have deliberated for all or part of nine days. Blankenship is charged with conspiring to break safety laws and defrauding mine regulators at West Virginia's Upper Big Branch Mine and lying to financial regulators and investors about safety. The coal mine exploded in 2010, killing 29 men. (AP Photo/Tyler Evert) (The Associated Press)

Don Blankenship leaves the federal courthouse with his attorneys after the verdict in his trial in Charleston, W.Va., Thursday, Dec. 3, 2015. The former Massey Energy CEO was convicted Thursday of a misdemeanor count connected to a deadly coal mine explosion and acquitted of more serious charges. (Tom Hindman/Charleston Gazette-Mail via AP) MANDATORY CREDIT (The Associated Press)