There's a warning out about traditional christmas lights.
A CNN investigation shows that the wire coating itself could pose a hazard to your family's health.
Every year Ronica Dhaliwal decorates her christmas tree, but she never worried about her christmas lights.
"You know, plug it in safely and use the proper outlet and that kind of thing..."she says confidently.
But lights contain lead - most boxes display labels, saying in part, "This product contains chemicals including lead" and "wash hands after use."
That worries medical experts like Dr. Leo Trasande, a specialist in children's environmental health at New York's Mount Sinai School of Medicine.
Trasande explains, "There is no level at which lead exposure is safe. Even at one microgram/decileter -- the lowest level in a person's blood stream that we can detect -- that level has been associated with cognitive impairment in children."
The use of lead as a fire-retardant in the lighting cords is perfectly legal.
CNN bought lights from several large retailers and sent them to be tested at an independent lab, Quantex in New Jersey, using the Consumer Product Safety Commission's standard wipe test for lead in vinyl products, like miniblinds and toys.
We wanted to see if the lead in the cords' PVC coating would come off on someone's hands.
Dr. James Menoutis of Quantex Labs says, "You don't realize there's lead in it. You eat a cookie, you eat something without washing your hands, that exposure builds up in your body over time."
In all four brands of lights, Quantex found surface lead levels far exceeding the CPSC's recommended children's limit of 15 micrograms.
Three samples from each brand were tested. The results were startling.
GE brand showed lead from 68 to 109.1 micrograms, Wal-mart from 86.6 to 132.7 micrograms Sylvania brand from 59 to 70.3 miicrograms and Philips brand from a low of 3.2 -- well under the 15 microgram limit -- to 107.2 in another sample.
Dr. Trasande says those tests show children could be vulnerable.
Of all the companies whose lights CNN tested, none would go on camera.
But in written statements all expressed concern about safety. GE said : "...we take great precautions to make sure our products are safe."
Wal-Mart said: "The special coating around electrical wires on the light sets is necessary to pass the stringent safety and quality regulations."
And Sylvania said: "We encourage consumers to exercise common sense by keeping holiday lights and other electrical products away from the hands and mouths of children."
Philips said their lights, "...meet all American National Standards Institute/Underwriters laboratory requirements... Although Philips is working to reduce the physical amount of lead necessary..."
The CPSC says Christmas lights do not pose an elevated danger of lead exposure to children. And they say our tests on light cords using the CPSC's methods for blinds and toys is like comparing apples to oranges -- and is "rotten to the core."
However, in a prior interview -- not a response to our tests -- the Consumer Product Safety Commission advises children should still keep away from lights because they are electrical products, not toys.