The number of inmates being observed for possible infection with Legionnaires' disease at San Quentin State Prison near San Francisco has jumped from 71 to 85, but the number of confirmed diagnoses held steady at six, authorities said Tuesday.

Prison authorities said they have begun restoring some freedom of movement, as well as access to the law library and hot meals to inmates at the California prison who were put on lockdown to avoid infection when the outbreak began last week.

The disease, a sometimes deadly form of pneumonia caused by a bacterium found in water systems, is transmitted when people breathe it in via steam, mist and moisture in the air. For that reason, prison officials initially shut down the plumbing in the prison, which houses 3,700 inmates and has 1,800 employees.

On Tuesday, the Department of Corrections and Rehabilitations said in a news release that it would begin serving some hot meals at the prison after days of serving only boxed meals.

Late last week, officials brought in portable showers for inmates to use, but those on San Quentin's death row, among others, did not have access to them. On Tuesday, officials said they were working to provide access to the showers for those inmates.

Legionnaires' disease in Illinois killed four people and sickened 29 at Illinois Veterans Home at Quincy, the Quincy Herald-Whig newspaper reported on Monday, and a dozen people died in a recent outbreak in New York City.