herbicide until we could get around to removing the soil, the contaminated soil. >> in terms of removing the soil, i know you built a little bit of a barrier around the tree. you have gone to great lengths to get the contaminated soil from around the trees. they're old trees i, imagine you can't just uproots them. what was the process by which you took the soil away from the trees as best you could, while still trying to keep them standing and safe? >> it was really a two-step process. we built these plastic greenhouses to enclose the area around the two beds the trees are growing in. the purpose of this was to retain any dust that was blown up during the loosening of the soil around the roots. our first attempt at removing soil involved coming in with an