Four import companies have voluntarily recalled 150 million pieces of toy jewelry (search) sold in vending machines over concerns that some of it could pose a risk of lead poisoning (search), federal regulators said Thursday.

The recall, announced Thursday by the Consumer Product Safety Commission (search), is one of the largest in U.S. history.

About half of the 150 million pieces of toy jewelry actually contain lead, but because it is difficult to distinguish the lead jewelry from the non-lead jewelry, the industry decided to recall all of it, the commission said.

The four companies involved are A & A Global Industries Inc. of Cockeysville, Md.; Brand Imports LLC of Scottsdale, Ariz.; Cardinal Distributing Co. Inc. of Baltimore; and L.M. Becker & Co. Inc. of Kimberly, Wis.

The commission said it has received one report of lead poisoning in which a child swallowed a piece of toy jewelry that had been previously recalled. No reports of injury or illness have been received for the recalled products announced Thursday, the commission said.

Young children sometimes mouth or swallow items like these, and lead can leach from the jewelry into the child's body. Lead poisoning in children is associated with behavioral problems, learning disabilities, hearing problems and growth retardation.

The four firms have told the commission they have stopped importing toy jewelry with lead and will work on eliminating hazardous levels of lead in future imports of toy jewelry.

Commission chairman Hal Stratton urged parents to search their children's toys for this jewelry and throw away the recalled items.

"Well what we have found is that our tests show that about half of all of the jewelry that you see in vending machines around the country has unacceptable levels of lead," Stratton said in an interview with Associated Press Radio. "Lead poisoning is a very serious item and children get this jewelry and we're very concerned about them ingesting any of this," he said.

"Now, we have had lead poisoning incidents from this type of jewelry in the past," he said, "but that has been in connection with previous recalls earlier this year and last year and not in connection with this particular recall, so we have caught this one ahead of time we believe."

The commission collected and analyzed some samples of toy metal jewelry sold in vending machines and found ten products with lead. The industry volunteered to recall additional products.

The toy jewelry recall involves various styles of rings, necklaces and bracelets.

The rings are gold- or silver-colored with different designs and paint finishes and center stones in a variety of shapes.

The necklaces have black cords, black ropes or gold- or silver-colored chains. They have pendants, crosses or various geometrical designs and may include fake gemstones.

The bracelets include charm bracelets, bracelets with medallion links and bracelets with fake stones.

All the jewelry was manufactured in India.

Nancy Harvey Steorts, former chairman of the commission, said the "industry really needs to be commended" and called it "a model recall" because of the scope of the recall, noting that all of the jewelry was included in the recall even though not all of the jewelry was determined to have the potential for unacceptable lead levels.

Eugene Lipman of A & A Global Industries said safety was the top concern for the companies and that they volunteered the widespread recall so that they could eliminate any "confusion" regarding which toys were safe and which ones had the potential for lead poisoning.

Lipman said they were working with the agency, "setting testing methods, and no product is being imported." He said the companies will not import any more jewelry until the CPSC determines safety measures.

There are only about 2 million products remaining in vending machines nationwide and are expected to be completely cleared with in the next several weeks, Lipman said.

The toy jewelry was sold in vending machines nationwide from January 2002 through June 2004. The items cost between 25 cents and 75 cents.

Consumers should throw away the recalled jewelry. People seeking more information can contact an industry hot line at 1-800-441-4234 or visit the firms' Web site.