Two US soft drinks groups have hit back at claims that its flagship brands contain excessive levels of benzene.

Polar Beverages and In Zone Brands have been hit with lawsuits from consumers over the alleged amount of benzene contained in their products.

Lawsuits filed on Tuesday (11 April) in Boston and Tallahassee claim that independent tests have found levels of benzene exceeding safe drinking water standards in Polar Beverage's Polar Diet Orange Dry brand. In Zone Brands' Bellywashers label has also been named in the lawsuits.

The tests claimed that Polar Diet Orange Dry contained 9.1 parts per billion (ppb) of benzene, while BellyWashers 2/3 Less Sugar in the Spiderman bottle had 69 ppb, more than 13 times the level allowed in public water supplies. According to the US Environmental Protection Agency, the standard for tap water is 5 ppb.

Polar Beverages president and CEO Ralph D. Crowley insisted the company was "committed to ensuring the safety of our products through in-depth research and testing".

"Our products exceed the guidelines established by the Food and Drug Administration. When questions were raised about the levels of benzene in our Diet Orange Dry soda, Polar Beverages had Industrial Analytical Services conduct tests on it as recently as February. Their scientific studies showed no trace of benzene in our Diet Orange Dry," he told just-drinks yesterday.

In Zone Brands told just-drinks it was "surprised" at the launch of the lawsuit but said it was "very confident" about the "excellent quality" of its products. Nevertheless, the company added it was "addressing the matter seriously" and had asked "independent, third-party experts" were looking at the level of benzene in its products.

However, lawyers associated with the lawsuits demanded both companies stop selling the brand.

"Benzene is simply unfit for human consumption," said Andrew Rainer, a partner with the Boston firm of McRoberts, Roberts & Rainer, L.L.P., and a former state prosecutor. "That's why we have filed suit today, and are calling on Polar Beverages and In Zone Brands, the manufacturer of BellyWashers, to pull their products from store shelves."

The lawsuits come just two weeks after the US Food and Drug Administration played down rising concern over the presence of benzene in soft drinks.

"Based on currently available results from this limited survey," the FDA said in a letter to the Environmental Working Group, "the vast majority of beverages sampled … contain either no detectable benzene or levels below the 5 ppb limit for drinking water, and do not suggest a safety concern.

"FDA is continuing to sample beverages to gain more representative data on the current situation," the letter continues. "We intend to release our results when we have a more complete understanding of the current marketplace. Although the results to date are preliminary, they do not suggest a safety concern."