americanlicorice.com One-pound packages of Red Vines Black Licorice Twists have been recalled because they tested positive for high levels of lead, California officials said.

California health officials are warning fans of the popular Red Vines black licorice candy not to eat the treats because they tested positive for high levels of lead.

American Licorice Co. of Union City, Calif., issued a voluntary recall Wednesday for 1-pound bags of Red Vines Black Licorice Twists with a best before date of Feb. 4, 2013. It was not clear what volume of product had been recalled. Company officials did not immediately return NBC News calls seeking comment.

“American Licorice is notifying consumers not to eat this candy and asking they return to their place of purchase for a full refund,” company officials said in a statement on their website.

Analysis by the California Department of Public Health found that samples of the black licorice candy contained as much as .33 parts per million of lead, the agency said in a press release. That concentration could provide up to 13.2 micrograms of lead per serving, more than double the daily limit, for instance, for children younger than 6. Kids younger than that age should not consume more than 6.0 micrograms of lead per day from all dietary sources, health officials indicated.

No illnesses have been reported in connection with the candy, said Ronald Owens, a health department spokesman.

Officials are still investigating the source of the lead contamination, said Pat Kennelly, the department's food safety expert.

Lead can be dangerous to pregnant women and young children. It is a heavy metal that can be toxic to developing organs and may impair neurological development. Long-term lead poisoning has been linked to learning disabilities and other problems in children.

California officials warned that pregnant women and parents of children who may have eaten the candy to talk with their doctors to determine if medical testing is necessary.

Consumers who find the candy for sale are urged to call the CDPH complaint hotline at 1-800-495-3232 .

Related stories: