Of nearly 1,600,000 people imprisoned in the United States, about 31 percent of inmates have at least one disability, the Amplifying Voices of Inmates with Disabilities (AVID) Prison Project reports.

Officials with the project are working to enforce the Americans with Disabilities Act in prisons, many of which have disability coordinators, KUOW reports.

According to AVID, in recent years, there has been a rise in "the number of people with mental illness and developmental and cognitive disabilities in prison" and, as the country's prison population ages, more inmates are reporting physical disabilities, too.

More from AVID, emphasis mine:

While prison is hard for everyone, incarceration is even more challenging for inmates with disabilities. Research shows that inmates with disabilities are sentenced to an average of fifteen more months in prison as compared to other inmates with similar criminal convictions. The time they serve is also harder, with more sanctions imposed and less access to positive programming than other inmates. Prisoners with disabilities are also four times more likely to report recent psychological distress as compared to inmates without disabilities. In a system intended to control and sanction behavior believed to violate the many regulations that govern prison life, inmates with disabilities who need accommodations are often overlooked, ignored, or even punished.

According to KUOW, Washington prisons are part of the problem. One Washington inmate said he had to drag himself around when he was placed in segregation without his wheelchair, while another inmate who is mostly blind struggled to get around, they reported.

“I would go inside other people’s cells because I would get lost,” Tyron Gathings told KUOW. Gathings is featured in AVID's video, above.

Thankfully, there are local advocates working to improve conditions for inmates with disabilities.

“Their hard time is harder. ... Inmates shouldn’t be subject to these additional forms of punishment simply because they have a disability,” Rachael Seevers, an attorney with Disability Rights Washington, told the news station.

Read more about the project and hear stories from prisoners with disabilities here.