The state of Arkansas has obtained sufficient quantities of a lethal injection drug to execute eight men over a 10-day period next month.

There are currently 34 inmates on Arkansas’ death row.

The acceleration of death row executions seems sudden, in part because Arkansas hasn’t executed anyone since 2005, due to both legal challenges and difficulty obtaining the necessary lethal injection drugs. One reason for the rush could be impending expiration dates on some of the drugs it uses for executions.

Arkansas’ Department of Corrections relies on a three-drug protocol to carry out executions. First, midazolam — the controversial drug at the center of several high-profile botched executions in recent years — is administered to sedate the inmate. Then vecuronium bromide is provided to stop the inmate’s breathing, followed by potassium chloride to stop the heart.

Department of Corrections spokesman Solomon Graves said Monday that the state had acquired 100 vials of potassium chloride after its previous supply expired in January. Due to Arkansas’ drug secrecy law — upheld by the state Supreme Court last June — Graves will not have to disclose how much the drug cost or where it came from, but the AP reports the state got the drugs, which expire in August 2018, on March 8.

But the state has a limited window to use the potassium chloride before its supply of midazolam expires at the end of April. In the meantime, lawyers representing death row inmates are trying to stop Arkansas from using the midazolam at all, saying that the drug is an ineffective sedative that leaves an inmate vulnerable to feeling intense pain as they die.