HOUSTON (AP) — A federal judge has ordered the state to disclose the number of heat-related deaths that have occurred in Texas prisons since 1990.

U.S. District Judge Keith Ellison at a hearing Wednesday in Houston gave the state 30 days to comply.

The order comes as part of a federal civil rights lawsuit filed in 2013 that contends at least 13 inmates have died of heat-related deaths since 2007, including 11 in 2011 when a heat wave brought some of the hottest temperatures on record.

The Houston Chronicle reports (http://bit.ly/2hzkC3J ) the lawsuit argues more than 1,400 prison inmates, most of them elderly and disabled, are suffering "cruel and unusual punishment" by enduring extreme summer heat without air-conditioning.

There are 109 state prison facilities in Texas, with 30 that are air-conditioned in all housing areas.