A hookah is a waterpipe used for smoking flavored tobacco. The popularity of hookah bars and lounges is growing in the United States. The health risks associated with hookah smoking are generally thought to be greater than those of cigarette or cigar smoking, despite myths to the contrary. Hookah smoke contains significant amounts of nicotine, tar, heavy metals, and carcinogens. Hookah water filtration cools the smoke but does not filter it. A typical hookah session may last for an hour or more, and can be similar to smoking up to 100 cigarettes. In spite of this, attempts to exempt hookah bars and shisha (hookah tobacco) from policies restricting the sale flavored tobacco products and smoke-free laws have been successful in a number of jurisdictions.