DENVER — A day after giving up on efforts to call a special legislative session on oil and gas drilling, Gov. John Hickenlooper appealed to the public Thursday to decry possible ballot measures to curb the industry.

Hickenlooper joined dozens of industry allies to say that proposed ballot measures to increase drilling setbacks and add environmental protection rights to the state constitution could cost thousands of jobs.

"We all agree that putting a 2,000-foot setback in the state constitution, or attempting to resolve these issues in the November ballot, is a bad idea for Colorado," Hickenlooper said.

The oil and gas industry has said the ballot measures would ban drilling, though supporters of the ballot measures disagree.

Supporters of the ballot measures have until Aug. 4 to gather signatures to put those measures on ballots in November.

Hickenlooper emphasized that he believes the measures could have negative effects on the state's economy.

"These measures risk literally thousands and thousands of jobs," the governor said.

Joining the governor were members of the Coloradans for Responsible Reform, a coalition of business groups opposed to new limits on oil and gas drilling.