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EPA, W.R. Grace discuss OU3 dam, fire preparation

by Luke Hollister Western News
| April 30, 2019 4:00 AM

W.R. Grace showed plans to build a new spillway, improve their current dam in Operational Unit 3, as well as how they are mitigating potential future fires in the unit, Wednesday at a presentation in Libby.

Tony Penfold, a W.R. Grace remediation manager, said over the next 4-to-5 years a new spillway for the Kootenai Development Impoundment Dam will be built.

“The new spillway is designed for that cataclysmic storm that’s probably actually never gonna happen,” he said.

A W.R. Grace timeline showing estimated progress for the spillway construction estimated the cost to be $40 million, with completion by 2024.

Given it is on a superfund site, logistics of how to get concrete out there are still being worked on, he said.

W.R. Grace is trying to minimize any potential asbestos exposure for future workers in the area, he said. There are a lot of different ways to do this project but worker safety is forefront.

The final design of the dam is still “in flux,” he said. It might be 20 feet high, or it could be about 6 feet high for a “100-year” — or 1-percent-chance — storm.

Those details are up to the engineers and what they advise, he said. Though, W.R. Grace will probably go with something bigger than needed for a 100-year storm.

There have been a few years when the spillway has not flowed at all, he said. The most water seen through it has been about 6-to-8 inches deep.

When W.R. Grace gets the new 30-foot-wide spillway, water is going to be maybe an inch most of the time, he said.

Aside from the dam, W.R. Grace is also working to reduce the risk of fires on their land.

OU3 is basically all forest and timberland with no homes, he said. Work done up there is to ensure a good, healthy ecosystem and manage pests.

In the past couple of years, W.R. Grace opened up fire trails and cleared out roads so that, if there are any fires, the forest service can get in with firefighting teams, he said. Before contractors cleared it “you would need to go through with a machete” and would have no hope of getting through with a vehicle.

Outside of W.R. Grace property, they are looking to do some thinning and logging in order to create a more fire-resistant landscape, he said.

This is sort of the first two years of effort, and is a part of a much broader scale project, he said. W.R. Grace would like to create a zone to cut off fires, such as the 2018 Highway 37 fire, before they get further.

Some of the people potentially at risk to asbestos exposure in OU3 are firefighters doing dry mop-up activities without protection or working on site restoration, “playing around in the ash,” after a fire goes through, he said.

Studies regarding Asbestos getting in the smoke show it is “not really a risk,” he said.

Dania Zinner, a remedial project manager with the EPA, said there is a program in place to monitor air.

In the case of a huge fire, those air samples would be sent to EPA labs and then to the county’s public health officer to see if there are high levels of asbestos in the air, she said.

EPA studies show asbestos generally stays in the ash rather than in the smoke, she added.

Nathan Gassmann, with the U.S. Forest Service, said there is a 10-person crew on call, all week, dedicated to responding to any fires in OU3. The contracted crew will be available from mid-July to mid-September.

Last year, the Highway 37 fire put a lot to the test, he said. “This year, I think we are going to be in a good spot to be successful again.”