For more than a month, the U.S. Environmental Protection Agency has said Sandy did not cause significant problems at any of the 247 Superfund toxic waste sites it monitors in New Jersey and New York state.

But in many cases, no actual tests of soil or water are being conducted, just visual inspections.

The EPA conducted a handful of tests right after the storm, but could not provide details or locations of any recent follow-ups when asked last week. New Jersey officials point out that federally designated Superfund sites are EPA's responsibility.

The 1980 Superfund law gave EPA the power to order cleanups of abandoned, spilled, and illegally dumped hazardous wastes that threaten human health or the environment. The sites can involve long-term or short-term cleanups.

Jeff Tittel, executive director of the Sierra Club in New Jersey, says officials have not done enough to ensure there is no contamination from Superfund sites. He said he was worried that toxins could leach into groundwater and the ocean.

"It's really serious, and I think the EPA and the State of New Jersey have not done due diligence to make sure these sites have not created problems," Tittel said.

The EPA said last month that none of the Superfund sites it monitors in New Jersey or New York sustained significant damage, but that it had done follow-up sampling at the Gowanus Canal site in Brooklyn, the Newtown Creek site on the border of Queens and Brooklyn, and the Raritan Bay Slag site, all of which flooded during the storm.

But EPA spokeswoman Stacy Kika did not respond last week to questions about whether soil or water tests had been done at the other 243 Superfund sites. The agency has not said exactly how many of the sites flooded.

"Currently, we do not believe that any sites were impacted in ways that would pose a threat to nearby communities," the agency said in a statement.

Politicians have asked similar questions. On Nov. 29, U.S. Sen. Frank J. Lautenberg (D., N.J.) wrote the EPA to request "an additional assessment" of Sandy's impact on Superfund sites in the state.

Elevated levels of lead, antimony, arsenic, and copper have been found at the Raritan Bay Slag site, a Superfund site since 2009. Blast furnaces dumped lead at the site in the late 1960s and early 1970s, and lead slag was also used there to construct a seawall and jetty.

The EPA found lead levels as high as 142,000 parts per million at Raritan Bay in 2007. Natural soil levels for lead range from 50 to 400 parts per million.

The EPA took four samples from the site after Sandy: two from a fenced-off beach area and two from a nearby public playground. One of the beach samples tested above the recreational limit for lead.

Early last month, the EPA said it was taking additional samples "to get a more detailed picture of how the material might have shifted" and would "take appropriate steps to prevent public exposure" at the site, according to a bulletin posted on its website. But six weeks later, the agency could not say what had been found.

The Newtown Creek site, with pesticides, metals, PCBs, and volatile organic compounds, and the Gowanus Canal site, heavily contaminated with PCBs, heavy metals, volatile organics, and coal tar wastes, were added to the Superfund list in 2010.

Some say the lead at the Raritan Bay site can disperse easily.

Gabriel Fillippeli, director of the Center for Urban Health at Indiana University-Purdue University at Indianapolis, said lead tends to stay in the soil but can be moved around by storm water or winds. Arsenic, which has been found in the surface water at the site, can leach into the water table, Fillippeli said.

"My concern is twofold. One is, a storm like that surely moved some of that material physically to other places," Fillippeli said. "If they don't cap that or seal it or clean it up, arsenic will continue to make its way slowly into groundwater and lead will be distributed around the neighborhood."

The lack of testing has left some residents with lingering worries.

The Raritan Bay Slag site sits on the beach overlooking a placid harbor with a view of Staten Island. On a recent foggy morning, workers were hauling out debris, and some nearby residents wondered whether the storm increased or spread the amount of pollution at the site.

"I think it brought a lot of crud in from what's out there," said Elise Pelletier, whose small bungalow sits on a hill overlooking the Raritan Bay Slag site. "You don't know what came in from the water." Her street did not flood, but she worries about a park where people go fishing and walk their dogs. She would like to see more testing done.

Thomas Burke, an associate dean at the Johns Hopkins School of Public Health, said both federal and state officials generally have a good handle on the major Superfund sites, which often use caps and walls to contain pollution.

"They are designed to hold up," Burke said of such structures, but added that "you always have to be concerned that an unusual event can spread things around in the environment." He noted that the storm brought in a "tremendous amount" of water, raising the possibility that groundwater plumes could have changed.

"There really have to be evaluations" of communities near the Superfund sites, he said. "It's important to take a look."

Officials in New Jersey and New York note that they have also been monitoring less toxic sites known as brownfields and have not found major problems.

The New York DEC said in a statement that brownfields in that state "were not significantly impacted" and that it has not planned further tests for storm impacts.

Larry Ragonese, a spokesman for the New Jersey Department of Environmental Protection, said the agency had done visual inspections of major brownfield sites and also alerted towns and cities to be on the lookout for problems. The agency is not getting calls voicing concerns, Ragonese said.

Back at the Raritan Bay Slag site, some residents want more information. And they want the toxic soil, which has sat there for years, out.

Pat Churchill, who was walking her dog in the park along the water, said she was still worried.

"You can't tell me this is all contained. It has to move around," Churchill said.