According to Pyrex, they made the switch to soda-lime glass in America over 60 years ago.
http://www.pyrexware.com/index.asp?pageId=30#TruthID6
and according to STATS.org:
"[...]the industry as a whole switched from borosilicate [...] in the 1980s for a variety of reasons, including the fact that soda lime was easier to melt and work with (fewer deformities in the glass). But one of the major reasons for moving to soda lime was environmental compliance: borosilicate glass produces far more emissions from a glass furnace, accounting, in part, for the presence of boric acid in the water and soil. And it was not economical for companies to install multi-million dollar filter systems."