WILMINGTON, Del. — Attorneys for current and former Delaware officials are asking a federal judge to dismiss a lawsuit filed by the family of a guard killed in a prison riot and five other correctional officers who survived.

Inmates took over a building at the maximum-security Vaughn Correctional Center in Smyrna in February, setting off an 18-hour standoff during which correctional officer Steven Floyd was killed.

The lawsuit alleges that state officials have ignored staffing and security issues at the prison for years, creating an unsafe work environment.

In court papers filed last week, attorneys for the state argue, among other things, that there’s no constitutional right to workplace safety and that the defendants are immune from liability because they didn’t violate a clearly established right.