glass, especially of the antique type,contains many weird & often toxic substances. Consider vaseline glass, which owes it's glowing yellow-green colour to uranium!
These subtances are actually in quite small concentrations, however, & they shouldn't be harmful. They are "locked up" in the substance of the glass itself. Minute amounts of leaching of these minerals or compounds may occur, for example, vaseline glass does give off radiation in the form of alpha, beta, & gamma rays.
The amount of radiation given off by vaseline glass is very small, & not thought to be harmful.
However,these minerals were very dangerous to the glassmakers who worked with them, especially in the old days when there were few concerns about worker's health & safety.
If the glass is cut, using wheels, or sanded, the fine dust particles created may be ingested & would be detrimental to one's health.
As for an item sitting safely in a cabinet or on a shelf as a decorative piece, it shouldn't be a cause for concern. However, I wouldn't recommend using items like this to contain food or drink.The use of lead in crystal glass has been an prominent example of this particular issue. Manufacurers have had to reduce the amount of lead in order to make it safe to use for drinking glasses, & old lead crystal is seen as potentially unsafe for food & beverage use.
Glass chemistry is still a rather mysterious science, more like alchemy in many ways, & much of it's practice is not fully understood. Glassmakers also like to keep their methods secret!
Arsenic (in various oxide forms) was used, along with other minerals such as tin oxide, to create opaque milk glass.
The bone ash also contributed to creating a milky effect with fiery opalescent qualities.
Hope this helps!