The consumer advocacy group Center for Science in the Public Interest (CSPI) is urging the Food and Drug Administration (FDA) to put safety warnings on energy drinks, according to Reuters. The drinks have been linked to 17 deaths in the past two years.

The group wants the warning labels to tell consumers about the risk of heart attack, convulsion, and other adverse reaction to energy drinks.

CSPI says that while no study has proven that energy drinks have caused these deaths, 34 people have died in the United States in the past 10 years after consuming Monster, Rockstar or 5-Hour Energy. The group also is asking the FDA to reduce the amount of caffeine legally allowed in energy drinks to 71 milligrams per 12 ounces. This is the amount allowed in colas, the article notes.

A spokesperson for the FDA told Reuters, “This does not necessarily mean that the energy drink caused the death. Frequently there are other complicating factors, such as existing disease or medications the person may have been taking.”

“How many deaths will it take to get the FDA to protect consumers from energy drinks, with their high levels of caffeine and untested herbal and chemical ingredients?” CSPI Executive Director Michael F. Jacobson said in a news release. “Since the first batch of adverse event reports became public, the death count has essentially doubled, with dozens more injured. Yet the FDA is just standing by—no public warnings, no regulations, no testing required—nothing.”

In March, 2013, a group of health experts asked the FDA to restrict the amount of caffeine permitted in energy drinks. Eighteen physicians, public health experts and researchers wrote a letter to the FDA, saying the move is needed to protect children and teenagers from the potential risks of consuming large quantities of caffeine.