Hawaii hotspot created at least 129 volcanoes, more than 123 of which are extinct volcanoes, seamounts, and atolls, four of which are active volcanoes, and two of which are dormant volcanoes. They can be organized into three general categories: the Hawaiian archipelago, which comprises most of the U.S. state of Hawaii and is the location of all modern volcanic activity; the Northwestern Hawaiian Islands, which consist of coral atolls, extinct islands, and atoll islands; and the Emperor Seamounts, all of which have since eroded and subsided to the sea and become seamounts and guyots (flat-topped seamounts). Hawaiian volcanoes are characterized by frequent
Dormant Commerce Clause Board of California", . In this case the Dormant Commerce Clause is no longer "dormant" and the issue is a Commerce Clause issue, requiring a determination of whether Congress has approved, preempted, or left untouched the state law at issue. The second exception is "market participation exception". This occurs when the state is acting "in the market", like a business or customer, rather than as a "market regulator". For example, when a state is contracting for the construction of a building or selling maps to state parks, rather than passing laws governing construction or dictating the price of state park