SAN FRANCISCO (CBS SF) — A San Francisco law that requires a health warning label on advertisements for sodas and other sugary drinks will not go into effect on July 25 as scheduled.

U.S. District Judge Edward Chen, in a ruling filed on Tuesday, granted beverage industry groups a preliminary injunction blocking the law while they appeal a decision he issued in May in favor of the measure.

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Chen wrote that he expects the injunction to be in effect for only a brief time because the appeal to the 9th U.S. Circuit of Appeals is likely to be expedited.

In his earlier decision last month, Chen declined to grant a longer-term preliminary injunction that would have been in effect for months until a full trial is held on the lawsuit filed by the American Beverage Association and other groups.

Chen said in the previous decision that the required warning was factual and accurate and was justified by the city’s interest in protecting public health and safety.

But the judge said in Tuesday’s ruling that a short-term suspension of the law during the appeal was reasonable because there is “a plausible argument there are serious questions on the merits” of the industry lawsuit.

Chen said he was particularly concerned about a requirement that the warning must cover 20 percent of the space in an advertisement.

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The required notice would say, “WARNING: Drinking beverages with added sugar(s) contributes to obesity, diabetes, and tooth decay. This is a message from the City and County of San Francisco.”

The law applies to ads on billboards, posters, walls, bus shelters and transit vehicles, but not to newspaper and magazine ads, beverage containers and menus.

The Washington, D.C.-based American Beverage Association was joined by the California Retailers Association and California State Outdoor Advertising Association in the lawsuit filed last year.

They contend the measure violates their free-speech right by forcing them to display a message they don’t agree with, and that it also discriminates against a particular category of products.

The association said in a statement, “We appreciate Judge Chen’s ruling and look forward to presenting our case.”

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San Francisco City Attorney’s Office spokeswoman Andrea Guzman said, “Judge Chen recognizes that it is the first such law in the nation and out of an abundance of caution, wants to give the appellate court a chance to weigh in.”