Law firm McRoberts, Roberts & Rainer LLP have filed more class action lawsuits on behalf of a concerned consumer against In Zone Brands, who make Bellywashers drinks, and also the Talking Rain Beverage Company.
The suit alleged independent laboratory tests had shown both companies had drinks contaminated with benzene, a known carcinogen, above the five parts per billion legal limit for benzene in tap water across the US.
Benzene lawsuits have now been filed in Kansas, Washington DC, Florida and Boston. The trend puts soft drinks firms under greater pressure to eliminate or control benzene formation in their beverages.
Renewed concerns about its presence in soft drinks have grown since a Food and Drug Administration (FDA) scientist revealed to BeverageDaily.com in February that recent tests had again found some soft drinks with benzene above the US water limit.
The suspected source is two common ingredients - sodium benzoate and ascorbic acid (vitamin C) - in the drinks.
The FDA and soft drinks industry have known for 15 that these two ingredients could react to form benzene in drinks, as well as that exposing such a drink to heat could significantly raise benzene levels.
Despite this, no public announcement was made. The FDA instead privately agreed for the industry to "get the word out and reformulate", a BeverageDaily.com investigation found earlier this year.
The FDA has stressed that benzene levels it has found in recent testing did not pose an immediate health risk to consumers, but that some reformulation would be required.
The agency has also begun to question the accuracy of its own off-the-shelf tests, after work by independent scientist James Neal-Kababick exposed a problem.
Kababick, who claimed to have devised a better test for benzene, said the FDA's procedure exposed drinks to heat, which could cause more benzene to form in the drink and so skew results.
It was unclear why the FDA had not looked into this over the last 15 years, despite conducting several spot checks for benzene in soft drinks.
The agency re-opened its investigation into benzene in soft drinks last autumn, after it saw results from lab tests commissioned by lawyer Ross Getman and Larry Alibrandi, a concerned food scientist, who worked on soft drinks industry testing for benzene in soft drinks back in 1990.
The last couple of months has seen food safety authorities around the world testing drinks for benzene, as well as recalls on four drinks brands in the UK and demands for an explanation from the soft drinks industry.
The American Beverage Association told BeverageDaily.com reformulation did take place in 1990, but that some brands may not be aware of the potential for sodium benzoate and ascorbic acid to form benzene.