How Executions Take Place

If you aren't familiar with the state abbreviations used below, you can check this list on the U.S. Postal Service website.
Lethal Injection is now the standard execution method. Since the death penalty was reinstated in 1976, only about 150 executions have been by electric chair, about 10 by gas chamber and less than 5 by hanging or firing squad.
The Lethal Injection is usually 3 different drugs: one which numbs the person, one which paralyzes their muscles (including the lungs) and one which causes a heart attack.
2 states (OH and WA) now use only 1 drug for their Lethal Injections. They use the 1st drug, sodium thiopental, which is a numbing agent/anesthetic. In large doses it is fatal on its own. The states changed from the 3-drug method after questions over whether a smaller dose of numbing agent could leave a person feeling pain but unable to express it, especially after the 2nd drug which causes paralysis is administered.
States which still have Electrocution on the books: AL, AR, FL, KY, NE, OK, SC, TN, VA Most of these states, with the exception of Nebraska, also use Lethal Injection. Arkansas allows those prisoners sentenced to death before 1983 to choose between lethal injection and electrocution. Kentucky and Tennessee does the same for those sentenced before 1998. Oklahoma would use electrocution only if lethal injections are found to be unconstitutional (and firing squad if electrocution is also found unconstitutional).
States which still have the Gas Chamber on the books: AZ, CA, MO, WY All of these states also use Lethal Injection. Arizona allows prisoners sentenced to death before 1992 to choose between lethal injection and the gas chamber. Wyoming would use the gas chamber only if lethal injections are found to be unconstitutional.
States which still have death by Hanging on the books: DE, NH, WA All of these states also use Lethal Injection. Delaware allows prisoners sentenced to death before 1986 to choose between lethal injection and hanging. New Hampshire would use hanging only if lethal injections were not possible.
States which still have death by Firing Squad on the books: ID, OK, UT All of these states also use Lethal Injection. Oklahoma would use a firing squad only if lethal injections and electrocution are both found to be unconstitutional. Utah would use a firing squad only if lethal injections were not possible.