SAN FRANCISCO — Dennis J. Herrera, city attorney for San Francisco, sent a letter last week to Monster Beverage Corp. asking the Corona, Calif.-based company to provide evidence concerning the safety of its products for consumption by adolescents. Mr. Herrera issued the letter under provisions of California’s Unfair Competition Law that empower city attorneys to demand evidence for purportedly fact-based advertising claims.

Mr. Herrera noted that although Monster claims its energy drinks are “completely safe,” there is increasing evidence that the high caffeine levels in the products “are dangerous, particularly for the youth whom you target with your advertising.”

Specifically, Mr. Herrera asked for evidence supporting several facts that Monster makes on its products and web sites, including that its consumers “can never get too much of a good thing!” and that Monster and Monster Mega are safe for consumption except for “children, pregnant women or people sensitive to caffeine.” Mr. Herrera also questioned two statements in an Oct. 23 press release from Monster in which the company said, “Monster Energy drinks generally contain approximately 10 milligrams of caffeine from all sources per ounce” and Monster’s “products are and have always been safe.”

Responding to Mr. Herrera’s request, Monster said, “The company can document the legal basis by which its products are properly labeled dietary supplements, and third-party scientific documentation substantiates their safety.”

The safety of energy drinks has come under scrutiny recently after a wrongful death lawsuit was filed against Monster Beverage Corp. in mid-October.

Plaintiffs Wendy Crossland and Richard Fournier, parents of the late Anais Fournier and residents of Maryland, filed the lawsuit in the Superior Court of the state of California in Riverside. Anais Fournier, then 14, died on Dec. 23, 2011.

According to the lawsuit, Anais Fournier consumed a 24-oz Monster Energy drink on Dec. 16, 2011. The next day she consumed another 24-oz Monster Energy drink. The two cans together contained 480 mg of caffeine. Monster Energy drinks also contain guarana, which is a plant extract that contains caffeine, and taurine, which has an effect on cardiac muscles similar to that of caffeine, according to the lawsuit.

A few hours after drinking the second beverage, Anais Fournier went into cardiac arrest. Doctors at Johns Hopkins Hospital placed her in an induced coma in an effort to reduce brain swelling. She remained in the coma for nearly six days until a decision was made to terminate life support.

Responding to the lawsuit, Monster said, “Over the past 16 years Monster has sold more than 8 billion energy drinks, which have been safely consumed worldwide. Monster does not believe that its beverages are in any way responsible for the death of Ms. Fournier. Monster is unaware of any fatality anywhere that has been caused by its drinks.”