What do you do with the desiccant bags that come with IC shipments? I try to put them in my parts bins to avoid throwing them away. The drawers are not air tight, so I doubt it has any effect, but I hate to throw them away. I don't mind throwing one or two away, but I get quite a few each time I order a kit for a small build. As they started filling my trash while I was building a board last week, I wondered if throwing away all of these bags was bad for the environment. 
According to a supplier of desiccant bags and my municipal recycling coordinator, desiccant bags do not harm the environment when discarded in the regular trash.
A sales coordinator for Sud-Chemie told me they are Bentonite clay, which is non-toxic. They provided me a materials safety datasheet (MSDS) with further details. One thing that stood out is the section on first aid measures. In cases of accidental ingestion and inhalation, first aid is not needed. It says the desiccant is “non-toxic by ingestion”. The packets, however, can be a choking hazard for small children or pets.
I sent the MSDS to my the recycling coordinator for the city of Madison, WI. He said it is fine to discard this material in the trash. Madison is generally progressive about recycling and limiting pollution, so I tend to accept their assessment.
I wonder if there are any other lab practices that haven’t occurred to me that, opposite of the case of desiccant, appear benign but are actually harmful.
