By Aaron Mendelson

SACRAMENTO, Calif., Aug 30 (Reuters) - The California state legislature enacted a ban on plastic grocery bags on Friday near the end of its two-year session, a measure that if signed into law would become the first of its kind in America.

A number of cities and counties in California and other U.S. states, including Hawaii’s Maui County, have made it illegal for grocery stores to pack purchases in plastic. But at the state level, opposition from plastic bag makers has usually prevailed.

The California Senate voted 22-15 for the bill, which must be signed into law by Sept. 30 by Democratic Governor Jerry Brown, who has not signaled a position on the measure.

“Single-use plastic bags not only litter our beaches, but also our mountains, our deserts, and our rivers, streams and lakes,” said state Senator Alex Padilla, who sponsored the bill.

Padilla backed a similar measure last year but it failed by three votes. The fate of this bill was uncertain until the waning hours of the session after falling three votes short in the state’s Assembly on Monday.

But after picking up the support of the United Food and Commercial Workers Union, the bill passed a second vote in the Assembly.

The measure would ban grocery stores from handing out single-use grocery bags with customers’ purchases, and provide money to local plastic bag companies to retool to make heavier, multiple-use bags that customers could buy.

Environmentalists have pushed for banning plastic bags, which are cheaper for supermarkets to use than paper bags, but create mountains of trash that is difficult to recycle. In California, there is particular concern that the bags, when swept out to sea, could harm ocean life.

After the defeat of his earlier bill, Padilla won the support of some California-based bag makers by including the funding for retooling. But in recent months, out-of-state manufacturers campaigned against the bill, even producing television advertisements targeting Padilla, who is running for secretary of state.

Cathy Browne, general manager at Crown Poly, a plastic bag manufacturer in Huntington Park, California, said the bill would lead to layoffs at companies like hers.

More than 10 billion plastic bags are used in California each year, according to an estimate by Californians Against Waste, an advocacy group supporting the bill. (Writing by Eric M. Johnson; Editing by Sharon Bernstein and Mark Heinrich)