Some materials that would be stored in a proposed underground nuclear waste facility less than a mile from Lake Huron are hundreds of times more radioactive than was told to Canadian government officials considering the site.

That revelation was brought to light by Frank Greening, a nuclear scientist who once worked for Ontario Power Generation, the utility seeking the deep geologic repository to store low- to intermediate-radioactive waste in Kincardine, Ontario, about 111 miles northeast of Port Huron on the Canadian side of Lake Huron.

Greening’s finding, along with a February accident at a similar underground nuclear waste storage facility in New Mexico that left workers on the surface exposed to radiation, has left Canada’s joint review panel asking new questions about the viability of the Kincardine project, and residents up in arms.

The new findings heighten the concerns many have over the nuclear waste facility’s proximity to the Great Lakes, from which 24 million U.S. residents get drinking water and that makes possible Michigan’s $2-billion fishing, $4-billion boating and $18-billion tourism industries.

“I just think it’s a terrible, terrible idea,” said Shirley Liechty of Port Huron. “There are so many people who are dependent upon the Great Lakes. To think that they would risk life and livelihood by putting that there, it’s just incomprehensible to me.”

The understated radiation levels involved pressure tubes, a component of nuclear reactors through which nuclear fuel moves.

“Of all the wastes the nuclear industry has to deal with, fuel is the worst — but that is known and it’s treated differently,” Greening said. “The next is things like pressure tubes.”

The products created during atomic fission can deposit on the tubes, he said. With one type of radioactive fission by-product in particular, the metal cesium, OPG’s numbers “are 1,000 times lower” than the actual radioactivity level that can be expected, Greening said.

The Nuclear Waste Management Organization, a government agency responsible for long-term management of Canada’s spent nuclear fuel, has provided OPG with technical expertise on its application for the underground nuclear waste storage site.

Paul Gierszewski, the director of the organization’s safety and licensing division, responded to Greening’s letter “with the concurrence of OPG” and agreed with him that several pressure tube-related radioactivity estimates “were underestimated by more than a factor of 100.”

But that doesn’t change the ultimate conclusion that the repository will be safe, OPG spokesman Neal Kelly said.

“We have checked the revised radioactivities, and the safety case remains valid,” he said.

Greening questions that conclusion.

“You got these numbers wrong up front for when you put these materials in the ground,” he said. “Perhaps your numbers can’t be trusted on what happens if any of this is released back aboveground. Why would I trust your numbers now?”

The Joint Review Board also is asking OPG whether its worst-case scenarios for “accidents, malfunctions and malevolent acts” need to be revised in light of an incident at the Waste Isolation Pilot Plant, or WIPP, near Carlsbad, N.M., a facility similar to the one proposed in Kincardine.

On Feb. 14, radiation leaked from underground tunnels at the WIPP site, leading to radiation exposure for at least 17 workers on the surface. The contamination drifted more than 26 miles to the city of Carlsbad, though not at levels considered dangerous by experts.

The cause of the incident is still under investigation, and OPG officials are awaiting its findings, Kelly said.

“As information becomes available, OPG will review and determine what the implications or lessons learned would be for our proposed Deep Geologic Repository project,” he said.

The utility has already planned for contingencies, such as an underground vehicle fire that occurred at the New Mexico facility nine days before the release of radiation. Safety measures would include fire suppression technology on vehicles and throughout the underground facilities, Kelly said.

Once the Joint Review Panel reviews OPG’s responses, it will schedule additional public hearing days for input on the new areas of inquiry, panel spokeswoman Lucille Jamault said.

After a closing comments period for “registered participants” and OPG, the Joint Review Panel will submit an environmental assessment report to Canada’s Minister of the Environment “outlining its conclusions, rationale, and recommendations,” Jamault said.

After the minister decides on the significance of any adverse environmental effects, the Federal Cabinet will decide whether those effects are justified. The Joint Review Panel could then be authorized to make a decision on OPG’s application, Jamault said.

The government decision is expected within four months of the submission of the panel report to the Minister of the Environment, she said.

Meanwhile, lawmakers on the Michigan side of Lake Huron continue to voice concerns about the project.

“I’m pleased to hear that the Joint Review Panel is taking seriously” the radioactivity understatements and incident in New Mexico, said state Rep. Sarah Roberts, D-St. Clair Shores, who earlier expressed opposition to the underground waste storage facility before the Joint Review Panel in Canada.

“This makes me even more worried about the potential for this project being approved,” she said.