PITTSBURGH -- Allegheny County Executive Dan Onorato received a key endorsement in Pittsburgh on Wednesday.

The United Steel Workers officially endorsed Onorato for governor.

The announcement was made at the union headquarters downtown.

Onorato officially kicked off his petition drive for Pennsylvania governor Tuesday.

Onorato addressed supporters at a rally at the IBEW Hall on Pittsburgh's South Side.

Onorato said candidates need at least 250 signatures in 10 different counties to get on the ballot.

Democratic State Auditor General Jack Wagner, former Democratic state Rep. Joe Hoeffel and Republican state Attorney General Tom Corbett have also announced plans to run for governor.