BURLINGTON, Vt. – A Vermont law designed to let consumers know how much mercury some products contain could have an impact across the country.

The law, which was challenged in federal court but ultimately upheld, requires companies to label all mercury-containing fluorescent lamps, but it only applies to Vermont.

But many producers are labeling all of their products, said Ric Erdheim, senior manager for government affairs at The National Electrical Manufacturers Association in Roslyn, Va.

“They have no way of knowing what’s going to go to Vermont,” he said.

One of the goals of the Vermont law is to increase recycling of mercury-containing products that are banned from state landfills.

Instead, manufacturers successfully lobbied for rules that allow them to label lamps with the scientific symbol for mercury, “Hg.” The labels on lamps or their packaging will also include a directive to properly dispose of lamps and a Web site and toll-free number that helps consumers do so.

Lamp companies will contribute money for a Vermont public awareness campaign about the meaning of “Hg” and the importance of recycling mercury-containing products.

The campaign is critical for the labeling law to work, said Rich Phillips, director of the Environmental Assistance Division at the Vermont Department of Environmental Conservation. “It isn’t going to be effective without an education campaign as to what ‘Hg’ means,” he said.

State government and lamp makers represented by the National Electrical Manufacturers Association reached an implementation agreement this fall after almost five years of battling the 1998 law.