Benefits of Food-grade Silicone
Food-grade silicone is a highly stable material. Silicone doesn't react with any liquids or solids. It has a nonstick surface that does not release any carcinogens when it is scratched, and does not create any harmful fumes. According to Health Canada, "There are no known health hazards associated with use of silicone cookware."
Improper Use
Dangerous situations can arise if the silicone vegetable steamer you purchase is not used for its intended purpose or in a manner contrary to the manufacturer's guidelines. While overheating does not release toxic fumes, the silicone can melt, causes messes and/or burns if it comes into contact with skin. Silicone vegetable steamers should only be used as steamers, and never placed under a broiler or open flame.
Composition of Silicone
Not to be confused with the similar-sounding material silicon, which is used in computers, silicone is composed of natural silicon that has been bonded through a chemical process with oxygen. Silicon is abundant in nature, particularly in rocks, which accounts for its resistance to high temperatures.
Maximum Safe Temperature
Health Canada recommends that silicone not be exposed to temperatures above 428 degrees Fahrenheit (220 degrees Celsius). Over that heat threshold, the material begins to break down, melting into a hot liquid that can run and cause damage in your kitchen. Use of your vegetable steamer on the stove top should be safe, as the temperature of steam does not exceed the temperature at which silicone breaks down. Silicone is dishwasher safe.