The cost per square foot varies significantly in different geographical regions and is estimated based on the history of other similar completed projects in the region. The cost per square footage for an inpatient facility (type I) can vary from $250 to $600 in most other regions of the United States. This cost is affected by labor availability and labor costs and the market price for construction materials. Most recently, the escalating costs of steel, concrete, and petroleum have been major factors affecting the increasing construction costs of new hospital projects. Construction regulatory requirements specific to each state to ensure building integrity and public safety in the event of a natural disaster (seismic activity, flooding, hurricanes, or tornados) can significantly affect the cost of construction and the building cost per square footage. California has one of the highest cost per square foot projections because of stringent seismic requirements for stronger structural designs and an escalating cost of steel.