Supervisors closed out the summer session on Tuesday by unanimously adopting a sweatshop-free rule for city purchasing, a plan that its sponsors said had taken too long to pass but still deserved praise as a pioneering effort.

The measure, which will be phased in beginning with garments, requires city contractors to show their goods were not created using forced labor, child labor or other means designated as unsafe or inhumane. It also creates enforcement mechanisms and encourages the purchase of locally made goods in hopes of reversing years of outsourcing such mass-produced items to areas where prices are cheaper and labor laws less strict.

"It's really a feel-good experience," commented the legislation's principal sponsor, Supervisor Tom Ammiano, "to know that we have not turned our backs on our immediate neighbors as well as their extended family members around the globe."

Garments and textiles represent roughly $2.1 million of The City's $600 million in contracts. After the meeting adjourned, Valerie Orth, of the group Global Exchange, said San Francisco and Los Angeles are now officially backing higher standards for workers locally and internationally. She said the Sweatfree Bay Area Coalition would next hope to see other mayors around the region adopting similar provisions.

Mayor Gavin Newsom, who co-sponsored the legislation, is expected to sign it into law next month following a required second vote by the board.