The City has approved tax breaks for biotech companies, film productions and Twitter, but it drew the line Tuesday at providing them for businesses that hire ex-felons.

Supervisor Ross Mirkarimi, who introduced the legislation that would offer a $10,000 tax break for each hire, said it was intended to prevent crime.

But the proposal was blasted Tuesday by the more moderate members on the Board of Supervisors and failed in a 6-5 vote.

“It is a slap in the face to the tens of thousands of law-abiding San Franciscans that are waking up every day looking for work and can’t find work,” said Supervisor Mark Farrell.

“What message are we sending to them? There is no way I could support this.”

Progressive Supervisor John Avalos, who opposes the concept of tax breaks, also had reservations and voted against the legislation.

“Where do we stop the tax exemptions at the expense of our revenue that we need for our city? They add up after a while,” Avalos said.

Mirkarimi and supervisors Eric Mar, Jane Kim, David Campos and Malia Cohen were on the losing end in supporting the tax break.

Kim said having a record is a barrier for employment.

“There is a rationale behind singling out this population more than other populations,” she said.

jsabatini@sfexaminer.com