The Item reports that the Waste Management truck did in fact hit the bus, sending two to the hospital. Link to Item story.
If you know any details, please post them in the comments below. I snapped these while hurrying to my car in the MBTA garage on the way to work and did not have time to seek out additional information, nor did I want to get in the way of officials doing their job. They were clearly in the middle of investigating.
(Sorry for the blurry phone pics)
This image was sent by LH reader Lorin Buksa, who says the garbage truck t-boned the bus.