New York City officials had been hoping that companies would supply the state with detailed information on pickups or drop-off sites before the law’s effective date so the city could help promote the services on its Web site, through direct mailings and through its 311 help line. Few were forthcoming, the officials said.

To link the public with collection outlets, “people have to have a simple place to go for information,” said Robert Lange, director of the Sanitation Department’s Bureau of Waste Prevention, Reuse and Recycling.

Kate Sinding, a senior lawyer with the Natural Resources Defense Council, said the needs of consumers in the state varied widely depending on where they lived. “Most of these sites make it appear that the only way to return stuff is by going to a drop-off location,” Ms. Sinding said. “While that might be a viable option in many parts of the state, in others like New York City and rural areas, it will be more difficult.” Manufacturers in such areas will need to start providing and advertising collection events, she said.

Companies are relying on different methods to take back the products, including mail and collection posts at storefronts and in government and residential buildings, said officials with the State Department of Environmental Conservation, which will oversee the enforcement of the law.

So far, 69 manufacturers have registered their collection plans with the Environmental Conservation Department, which has posted a list of the companies’ Web sites online and invited consumers to submit feedback on compliance by the manufacturers. The department said it had no estimate on how many companies covered by law had failed to respond.