San Francisco has become the first major US city to effectively ban the sale and manufacture of electronic cigarettes. The city's board of supervisors unanimously endorsed legislation yesterday which backers said was necessary due to the significant public health consequences of a dramatic surge in vaping among youths. <br />''<br />''The ordinance says e-cigarette products sold in shops or online in San Francisco would need approval by the US Food and Drug Administration, which none currently has.<br />''<br />''<br />