Calphalon is considered safe due to its FDA approval. However, Calphalon cookware uses a non-stick finish that overlays anodized aluminum. According to Your Cookware Helper, if the non-stick surface wears off, acids can react with the aluminum and create toxicity.
Anodization is an electro-chemical process which makes aluminum, a naturally soft metal, harder and more durable. Through this process, aluminum becomes 30 percent harder than stainless steel. The end result is a product which resists the rigors of cooking, such as abrasion, corrosion and high temperatures. If properly maintained, anodized cookware does not lose its non-stick surface and can last for decades.