Glass has multiple unique properties that make it well suited for industrial use. Because its chemical makeup can be altered to meet specific product needs, the types of glass manufacture are vast. There are five general categories of glass manufacture: flat glass (windows, picture glass), container glass (bottles and jars), pressed and blown glass (light bulbs, ovenware, medical glassware), glass fiber (fiberglass insulation, material reinforcement, optical fibers), and products from purchased glass (assembled products, aquariums, art, mirrors, table tops).
Major consolidation in the glass industry in the nineties led to an increase in fiber optics and glass for electronics, as well as an increase in foreign ownership. Categories such as container glass, flat glass, and fiber glass are experiencing few advancements, but the overall demand remains consistent.
Throughout the eighties and nineties the glass industry experienced steady growth, and in 1999 shipped 28.4 billion dollars in products. Of the various different categories, purchased glass products came out on top at 10.8 million dollars in shipments, with pressed glass coming in second at 5.8 million dollars in shipments. Mineral wool and container glass sold close to the same amount, grossing 4.8 and 4.2 million dollars in shipments, respectively. Flat glass products shipped the least, at 2.7 million dollars. California, Ohio, and Pennsylvania had more than ten high-production glass plants, with states like New York, New Jersey, Indiana, and West Virginia each home to between 6 and 10 high-production glass plants. North Western states, such as Montana, Wyoming, North and South Dakota, and Idaho were completely void of operating production plants.
The glass industry, like many other industries that depend on large product generation, is attempting to cut back on energy use and environmental waste. In 1994, the glass industry invested 250 million dollars in pollution control associated with equipment, material, energy, and supplies. Control of air emissions produced by machinery consumed a large amount of the sum, with 74 percent of the total spent on pollution control associated with operating equipment. Fuel and electricity costs also accounted for 19 to 40 percent of pollution control costs, especially in container glass, glass wool, and specialty glass product niches of the market. Changes are continually being made to the manufacturing process in an effort to further reduce environmental harm and reduce overall energy use.