ORANGE, Conn. — IT’S been called “America’s most ‘open’ secret”: According to the Bureau of Justice Statistics, around 80,000 women and men a year are sexually abused in American correctional facilities. That number is almost certainly subject to underreporting, through shame or a victim’s fear of retaliation. Overall, only 35 percent of rapes and sexual assaults were reported to the police in 2010, and the rate of reporting in prisons is undoubtedly lower still.

To tackle the problem, Congress passed the Prison Rape Elimination Act, signed into law by President George W. Bush in 2003. The way to eliminate sexual assault, lawmakers determined, was to make Department of Justice funding for correctional facilities conditional on states’ adoption of zero-tolerance policies toward sexual abuse of inmates.

Inmates would be screened to identify possible predators and victims. Prison procedures would ensure investigation of complaints by outside law enforcement. Correctional officers would be instructed about behavior that constitutes sexual abuse. And abusers, whether inmates or guards, would be punished effectively.

But only two states — New Hampshire and New Jersey — have fully complied with the act. Forty-seven states and territories have promised that they will do so. Using Justice Department data, the American Civil Liberties Union estimated that from 2003 to 2012, when the law’s standards were finalized, nearly two million inmates were sexually assaulted.