The gurney in the death chamber in Huntsville, Texas. Pat Sullivan/AP

Texas filed a lawsuit Tuesday against the FDA after the agency impounded a shipment of a lethal injection drug in July 2015, and has failed to make a move since.

According to multiple sources, Texas tried to import 1,000 vials of sodium thiopental (a barbiturate anesthetic) from Harris Pharma in India, but the FDA detained the execution drugs at George Bush Intercontinental Airport, where it has held them for the past 17 months.

The lawsuit was filed to try to force the FDA into making a decision on the quarantined package, saying the decision should be made in a “reasonable” amount of time, which 17 months is not.

“There are only two reasons why the FDA would take 17 months to make a final decision on Texas’ importation of sodium thiopental: gross incompetence or willful obstruction,” Texas Attorney General Ken Paxton said in a prepared statement.

While the FDA does not comment on current litigation, the agency has made it clear in the past that sodium thiopental has no legal uses in the U.S., which, theoretically, would lead to the agency halting the shipment en route to Texas. Meanwhile, Texas argues that the drug should be allowed to be imported under a "law enforcement exemption." Sodium thiopental is not available from any U.S. manufacturer.

In recent years, U.S. pharmaceutical companies have either stopped making execution drugs, or barred sales of these drugs for lethal injection use. Thus, states have had to turn to compounding and foreign pharmaceutical manufacturers. A state law that took effect in September allows Texas to withhold the identity of its lethal injection drug provider.

According to the Washington Examiner, nine executions are scheduled in Texas for the first six months of 2017, and the state has enough drugs to carry them out. But, beyond that is uncertain. Texas tops the nation in capital punishment, carrying out 538 lethal injections since reinstatement of the death penalty in 1976.

Previously, Texas employed a three-drug protocol for lethal injections. As of October 2013, the state uses a one-drug protocol for lethal injections using pentobarbital obtained from a compounding pharmacy.