NEW YORK – The City Council voted 40-6 Wednesday to ban metal baseball bats for high school teams citywide, a law that supporters say would make the game slower and safer.

The measure was not certain to become law, though, because Mayor Michael Bloomberg said he was not sure whether he would veto or sign it.

The bill’s sponsors say non-wood bats produce faster and harder hits that can be dangerous for young players.

Opponents, including Little League Baseball and sporting goods makers, say there is no scientific evidence proving metal bats pose more of a risk than wooden bats. They say the anti-metal movement relies on emotional anecdotes over concrete data, and some have indicated they will take the matter to court.

Similar measures have been proposed by youth leagues and lawmakers in other states, including New Jersey, where a batted ball struck a 12-year-old boy in the chest, sending him into cardiac arrest. He was revived by spectators but remained in a coma for months.

Councilman Lewis Fidler, one of the bill’s co-sponsors, said Wednesday that by passing this law, “we’ll never know whose child was saved from a coma, or from worse.”

“For those who have doubt about it – if you’re going to have doubts, you err on the side of kids,” he said.

In 2005, an American Legion Baseball study found no substantial scientific proof to support the argument that wooden bats are safer than metal bats, which have been in use since the early 1970s.

Years ago, council members tried to pass a similar but stricter measure that applied to younger children and leagues. It was quite broad, and it eventually failed to pass.