Be Careful, and look for more of these "little piles"... I'd get that wood sealed up in plastic, and if possible, out of the building if you rely on wood framing or a timber frame to hold the roof up! If you start seeing any spread -- and it's starting to get away from you, take infected pieces outside and BURN IT!!!!!
These little critters are not all that hard to kill, but they can spread to other parts of your shop or house. End result could be a frame collapse or other extensive damage.
I just built a timber frame (a.k.a. "Post & Beam") house, made from a re-purposed 1852 Hemlock frame from an old house being torn down. We had all sorts of nice-looking beams left over, and stickered out under cover in the yard, with hopes of using them to build a pergola, a porch, and even a chicken coop. Just before snowflakes flew, I checked, and found many of them were infested with powder-post beetles.
On New Year's eve, we have a beauty of a bonfire! I'm not letting these little buggers infest my house in order to save a few dozen old beams.