Here preliminary research shows the possibility of underground CO2 conversion to calcium carbonate. It's has a number of people nervous, for the area is just recovering from one government "oops". That oops created the Hanford nuclear "downwinders" of eastern Washington and Idaho.

I think you're conflating the Hanford project with WPPS (fancifully referred to as WOOPS, since it turned out to be such a massive boondoggle); it was Hanford that released radiation sprinkling it on the downwinders - of which I'm one, about the last batch to get a dose. People where I grew up in Eastern Oregon used to just suddenly up and die for no reason.

I've read about sequestering CO2 in the Columbia River Basalt - fascinating idea. The volcano or volcanoes that created the basalts were utterly awesome in their power - repeatedly flooded everything east of the Cascades, pretty much, about 15 million years back.

No, not confusing. The whoops was whoops, WPPS later changed to Avista, since then becoming a rather decent utility. The oops was the government converup/denial of radiation leakage from Hanford.

One of the dislikes of the sequestration is that once again their "good for nothing" desert has found a use, where they will have many new coal fired power plants to deal with. The coal is imported, the power and dollars are exported, and they are left with the mess, again. Here's hoping the mess really does calcify.