An environmental group has filed a lawsuit in San Francisco's Superior Court alleging that some wine vinegars contain small amounts of lead.

The lawsuit claims that some wine vinegars can become contaminated with lead during the manufacturing process, and that the highest level of contamination is found in Modena-style balsamic vinegar, reported the Associated Press.

The Environmental Law Foundation is suing several manufacturers and retailers of wine vinegars under California's anti-toxics law, which says that businesses must warn consumers about potentially harmful toxins.

The group wants retailers to make sure their suppliers provide test evidence that their product meet state safety levels for lead. If the safety levels are not met, the product should carry a warning notice, the group says.

Michele Corash, an attorney representing wine vinegar manufacturers named in the lawsuit, said the suit was "completely groundless".