low-thermal-expansion glassware products, whose resistance to chemicals, electricity, and heat made it ideal for laboratory glassware and kitchenware. In Pyrex (trademarked as PYREX and pyrex) is a type of borosilicate glass developed by Corning Incorporated in 1908. Pyrex was first introduced to the public in 1915, as a brand of clear, low-thermal-expansion glassware products, whose resistance to chemicals, electricity, and heat made it ideal for laboratory glassware and kitchenware. In the 1930s, Corning expanded the brand to include kitchen prod Older clear-glass Pyrex manufactured by Corning, International Cookware's Pyrex products, and Pyrex laboratory glassware are made of borosilicate glass. According to the National Institute of Standards and Technology, borosilicate Pyrex is composed of (as percentage of weight): 4.0% boron, 54.0% oxygen, 2.8% sodium, 1.1% aluminium, 37.7% silicon, and 0.3% potassium. According to glass supplier Pulles and Hannique, borosilicate Pyrex is made of Corning 7740 glass and is equivalent in formulation to Schott Glass 8330 glass sold under the "Duran" brand name. Data sheets for Corning 7740 give its composition (approximate percentages) as 80.6% SiO2, 13.0% B2O3, 4.0% Na2O, 2.3% Al2O3, and 0.1% miscellaneous traces. Schott 8330 data sheets list its composition (again with approximate percentages) as 81% SiO2, 13% B2O3, 3.5% Na2O, 2% Al2O3, and 0.5% K2O. Starting around the 1950s, Corning began making Pyrex out of thermally tempered soda–lime glass, instead of borosilicate glass, due to lower manufacturing costs. Some plants moved to tempered soda–lime formulations, while others continued to produce borosilicate Pyrex. Herb Dann, a designer at Corning from 1961 to the 1990s, noted that by the time the consumer products division was sold in 1998, Corning had mostly switched to soda–lime glass for "almost all" of its tableware products. The exception to this was the 13"×9"×2" pan, which was never produced with soda–lime. Phil Ros Pyrex (trademarked as PYREX and pyrex) is a type of borosilicate glass developed by Corning Incorporated in 1908. Pyrex was first introduced to the public in 1915, as a brand of clear, low-thermal-expansion glassware products, whose resistance to chemicals, electricity, and heat made it ideal for laboratory glassware and kitchenware. In the 1930s, Corning expanded the brand to include kitchen products made of soda–lime glass and other materials. In 1998, Corning Incorporated spun off its kitchenware division, including Pyrex cookware. Currently, Pyrex dishes are manufactured by Corelle Brands in the United States and International Cookware in Europe. Corning Incorporated Older clear-glass Pyrex manufactured by Corning, International Cookware's Pyrex products, and Pyrex laboratory glassware are made of borosilicate glass. According to the National Institute of Standards and Technology, borosilicate Pyrex is composed of (as percentage of weight): 4.0% boron, 54.0% oxygen, 2.8% sodium, 1.1% aluminium, 37.7% silicon, and 0.3% potassium. According to glass supplier Pulles and Hannique, borosilicate Pyrex is made of Corning 7740 glass and is equivalent in formulation to Schott Glass 8330 glass sold under the "Duran" brand name. Data sheets for Corning 7740 give its composition (approximate percentages) as 80.6% SiO2, 13.0% B2O3, 4.0% Na2O, 2.3% Al2O3, and 0.1% miscellaneous traces. Schott 8330 data sheets list its composition (again with approximate percentages) as 81% SiO2, 13% B2O3, 3.5% Na2O, 2% Al2O3, and 0.5% K2O. Starting around the 1950s, Corning began making Pyrex out of thermally tempered soda–lime glass, instead of borosilicate glass, due to lower manufacturing costs. Some plants moved to tempered soda–lime formulations, while others continued to produce borosilicate Pyrex. Herb Dann, a designer at Corning from 1961 to the 1990s, noted that by the time the consumer products division was sold in 1998, Corning had mostly switched to soda–lime glass for "almost all" of its tableware products. The exception to this was the 13"×9"×2" pan, which was never produced with soda–lime. Phil Ross, an independent consultant to the glass industry, whose clients included World Kitchen, said in 2008 that the U.S. industry as a whole switched in the 1980s from borosilicate to soda–lime owing to it being easier to melt and work with, as well as being more environmentally friendly due to lower emissions from the glass furnace used. He noted it was not economical for companies to install multi-million dollar filter systems. This change was justified by stating that soda–lime glass has higher mechanical strength than borosilicate—it has around twice the strength—making it more resistant to physical damage when dropped, which is believed to be the most common cause of breakage in glass bakeware. However, its thermal shock resistance is lower than borosilicate's, leading to potential breakage from heat stress if used contrary to recommendations. Borosilicate's shock resistance is around three times higher than soda–lime. The differences between Pyrex-branded glass products has also led to controversy regarding safety issues—in 2008, the U.S. Consumer Product Safety Commission reported it had received 66 complaints by users reporting that their Pyrex glassware had shattered over the prior ten years yet concluded that Pyrex glass bakeware does not present a safety concern. The consumer affairs magazine Consumer Reports investigated the issue and released test results, in January 2011, confirming that borosilicate glass bakeware was less susceptible to thermal shock breakage than tempered soda lime bakeware. They admitted their testing conditions were "contrary to instructions" provided by the manufacturer. STATS analyzed the data available and found that the most common way that users were injured by glassware was via mechanical breakage, being hit or dropped, and that "the change to soda lime represents a greater net safety benefit."