California fires live updates: At least 10 fire-related deaths, medical examiner says

An emergency message telling Los Angeles County residents Thursday afternoon that an evacuation warning had been issued for their area was sent in error, officials said.

The alert was intended for residents near the Kenneth Fire but was mistakenly issued countywide, officials said.

"Recent @ReadyLACounty alert to evacuate was sent in ERROR. Evacuation orders have not changed. See map for actual @LACity evacuation orders for some selected areas, ONLY!" LA City Emergency Management Department tweeted.

The message, sent just before 4 p.m. local time, told residents to "remain vigilant of any threats and be ready to evacuate."

Victor Shaw is among those who lost their lives, with his sister Shari Shaw telling ABC News he died in a heroic attempt to defend his home in Altadena. The 66-year-old's body was found in front of the home, a garden hose still in his hand.

"I can't imagine what he might have been thinking, how he might have been so frightened," Shari Shaw said. "And I couldn't be here, I couldn't be here to save him. I couldn't be here, that's what hurts the most."

Shaw lived in the family home since 1965, and had health issues that impacted his mobility.

In Altadena, an area north of Pasadena, the Eaton Fire broke out Tuesday, growing to more than 13,000 acres. Up to 5,000 structures -- including businesses and homes -- have been damaged or destroyed, authorities said.

As firefighters work to contain the slew of brush fires spreading across Los Angeles County, among the emergency responders on Thursday were nearly 800 incarcerated individuals, the California Department of Corrections and Rehabilitation (CDCR) confirmed to ABC News.

The prisoners, who voluntarily sign up to be a part of the Conservation (Fire) Camps program, are embedded with the California Department of Forestry and Fire Protection crew members (CalFire).

The participating individuals are paid between $5.80 and $10.24 per day plus $1 an hour when responding to active emergencies, according to CDCR.

"CDCR Fire Camp Program firefighters are proud to be embedded with CAL FIRE personnel to protect lives, property, and natural resources in Southern California," the law enforcement agency said in a statement.

Incarcerated firefighters have been working "around the clock" cutting fire lines and removing fuel from behind structures to slow fire spread, according to the agency, which called the program a source of "crucial support" during emergencies.

The exact number of hours the incarcerated crew members have worked since brush fires erupted in Los Angeles on Tuesday was not immediately clear.

UCLA Health told ABC News on Thursday they have treated 30 patients with fire-related injuries, up from 21 on Wednesday. The injuries were primarily smoke inhalation and burns, and most patients were treated and released, the hospital said.

The LA County Department of Health Services also told ABC News on Thursday that their medical facilities have treated four patients for illness and injuries related to ongoing fires, including one patient in critical condition.