The lead from lead-soldered cans leaches into the contents of the can but acidic foods are especially susceptible. Canned fruit, fruit juices, and tomato sauce are primary targets for lead contamination. A newly opened can of juice will contain a lead concentration exceeding the maximum contaminant level, while an open can of juice remaining in the refrigerator for a few days will have dangerous levels due to oxidation. Instead, the FDA urged the domestic food canning and packaging industries in the mid 1970's to remove lead solder from cans on a voluntary basis. Since then, the percentage of cans using lead solder has been reduced from 90 percent in 1979, to about 16 percent in 1987.
Some manufacturers still continue to use old equipment and imported cans have no regulations.