Bad news for fans of the colorful novelty drink called tapioca tea, or boba tea: The sugary specialty beverage, generally milk-based and filled with chewy balls of tapioca, may also include cancer-causing chemicals known aspolychlorinated biphenyls or PCBs, the Daily News reports.

German researchers from the University Hospital Aachen have reportedly found traces of the carcinogenic chemical in tapioca ball samples. The tapioca was taken from an unnamed chain in northwest Germany and originated in Taiwan, according to the Daily News.

"[What we found] includes in particular styrene, acetophenone, and brominated substances that shouldn't be in food at all," scientist Manfred Möller, of the Institute of Hygiene and Environmental Medicine at the University Hospital Aachen, told German newspaper The Local, notes the AFP.

According to the EPA, PCBs belong to a broad family of man-made organic chemicals manufactured between 1929 and 1979. The chemicals still exist in the environment despite their U.S. manufacturing ban. Ranging in toxicity, PCBs have been shown to cause cancer, as well as a variety of other adverse health effects on the immune system, reproductive system, nervous system and endocrine system, the government site continues.

Bubble tea has gained widespread popularity in recent years across Europe, and Germany in particular, after already converting young people across North America. German McDonald's have even begun selling the dessert beverage as part of its recently revamped McCafe menu, the Independent reports.

The cancer concerns were compounded by another public health warning, released earlier in August by the country's German Federal Institute for Risk Assessment. German authorities warned that the beverage's hallmark gummy balls, may pose a choking risk.

"Especially with children aged up to four years, there is a risk of foreign objects accidentally entering the lungs," said Dr. Andreas Hensel in a press release on the Institute's website. "And that is precisely what can happen when the bubbles are sucked up through a straw."

UPDATE: According to Taiwan's Central News Agency, a leading manufacturer of bubble tea drink ingredients has since disputed the researchers' claims. Wang Chun-feng, chairman of the Possmei Corp., held a press conference Tuesday from his offices in New Taipei, to defend the safety of his products. Meanwhile, an official from Taiwan's Food and Drug Administration also refuted the German safety warnings, calling into question the authenticity of the test results.

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