Gee, that was fast
"Thank you for contacting World Kitchen, LLC
The older Corningware material was discontinued for production in the
US in 1995 amid information that the manufacturing process produced many
harmful by products into the atmosphere and environment. Stoneware
products are more environmentally safe to manufacture, while also
provided greater fluctubility for a larger selection of colors and
patterns.
We do not recommend continuing to use any item that may be cracked of
chipped as usage of a defective piece may cause it to break further.
Our specifications are that stoneware products and glazes such as
Corningware, are made of clay-based materials and glazes used
throughoutthe industry. Decorations, if present, are made from low-lead
enamels and fired at temperatures exceeding 1000 degrees F, which binds
any heavy metals both physically and chemically so that their release is
minimized.
Please note that to satisfy requirements concerning consumer warnings
onpackaging at time of sale and/or advertisement in the state of
California (so-called California Proposition 65), only traces of heavy
metals (including lead) are permitted. The current limit for presence
of leachable lead in order to satisfy California requirements is no
morethan 0.100 ppm (1 tenth of one part per million) when obtained under
test conditions. At no time have our results exceeded those which are
permissible under the guidelines mentioned above (which are believed to
be the most stringent in the world). Also note that tests for the
presence of heavy metals are conducted for World Kitchen by
internationally certified, third-party laboratories under strict
conditions, by trained technicians, and using atomic absorption
spectrophotometry analysis following carefully monitored preparation.
These steps are necessary to minimize any possibility of contamination
or false reading during preparation, testing or analysis.
For further assistance, please contact our Help Center at 800-999-3436.
Representatives are available from 8am to 6pm, EST, Monday through
Thursday and 8am to 5pm on Friday, and will be more than happy to assist
you."
So, now it's the ENVIRONMENT!
Better discontinue Pyrexware and Corelle Vitrelle, then. Same raw materials (Pyroceram was the result of a lucky accident when a batch of Pyrex overheated, turning it from transparent to opaque while strengthening it and imparting the ability to survive sudden temperature changes), just different manufacturing processes.