I don't believe Co-60 is capable of activating (making radioactive) other materials to any significant degree, so the danger is really only from direct exposure to the source material. So you get irradiated, but you don't become radioactive. If they were handling the material directly, there's a chance they contaminated themselves and their clothing, which could be transmissible. (c.f. Goiânia incident "[The scrapyard owner's daughter] was also fascinated by the blue glow of the powder, and applying it to her body, showed it off to her mother. Dust from the powder fell on the sandwich she was consuming.")

Obviously the guys opening the shielding and anyone in the vicinity of where that happened, where it was stored, or dumped is at risk, but it also sounds like the sources were encapsulated into pellets which makes incidental dust contamination much less of a problem than in previous incidents where it gets broken up and mixed with dirt, etc.