SACRAMENTO, Calif. (AP) — A federal judge is considering ordering all California prison employees and inmate firefighters to be vaccinated.

The move comes as the state tries to head off another coronavirus infection surge driven by the more contagious delta variant.

Federal receiver Clark Kelso told U.S. District Judge Jon Tigar on Thursday that efforts to encourage voluntary vaccinations among staff haven't been enough. He asked the judge to order that no employees be allowed into prisons unless they prove they’ve been vaccinated or have a religious or medical exemption.

Kelso also wants to bar in-person visits for inmates who aren’t vaccinated and don’t have an exemption.