"In a tradition dating back to medieval times, growers in Modena, Italy, are deep into the grape harvest, the first step in making their famed balsamic vinegar. Cooking the grapes releases rich juice that is then stored in vintage barrels. At least a dozen years of fermentation and evaporation reduces the wine to a sweet, fragrant elixir. Thousands of miles away, in California, signs in grocery stores warn shoppers about exposure to a dangerous metal in many balsamic and red wine vinegars. Although the amount of lead in vinegar is small, experts say regularly consuming it may pose a risk, particularly to children. Eating one tablespoon a day of some vinegars can raise a young child's lead level by more than 30 percent. For this report, Environmental Health News had an expert calculate children's doses and also hired an independent lab to test two bottles. Consumers want to know if vinegars are safe, but there are no easy answers."