EPHRATA — The last Grant County PUD employee who was listed in critical condition at Harborview Medical Center in Seattle has improved to serious condition. Both patients in Harborview are now listed in serious condition, said Susan Gregg, hospital spokesperson.

The employee, identified as a man in his 40s, was injured in an Oct. 8 explosion at Priest Rapids Dam. He was one of six employees hurt and is one of two still hospitalized at Harborview. Both are still in the intensive care unit and both will be undergoing surgery for their burns.

The second employee, also a man in his 40s, is “awake and alert,” Gregg said.

People who want to send messages of support can email the hospital at www.uwmedicine.org/patient-resources/email-patient. People who don’t have the patients’ names can identify the message destination with “dam explosion patients in intensive care,” Gregg said. The family of one of the patients, Michael Stalcup, has published a mailing address for cards. It’s Michael Stalcup, Harborview Medical Center, 325 Ninth Ave., Seattle, WA 98104-2420.

All six people suffered burns in the explosion, which has been traced to a circuit breaker in one of the dam’s 10 generators, although PUD officials haven’t identified which one. The breakers serve as the main on-off switches for the generators and the unit affected by the explosion was taken out of operation at the time of the incident, said Chuck Allen, PUD public information specialist.

All injured employees were power plant operators or electricians.

One of the six was treated and released within a day of the explosion, while the other five were airlifted to Harborview. Three have since been released.

A donation fund for all six victims was established at Granco Federal Credit Union, 217 Southwest Alder St, Ephrata. Donations should be marked for the “Priest Rapids Family Fund.” Donations also can be mailed to Granco, PO Box 127, Ephrata, WA 98823. Stalcup’s friends have set up a separate fund for him on the website GoFundMe.com.

The PUD is conducting an investigation into the cause of the explosion, and the generating unit won’t be put back into service until the investigation is complete, Allen said. The Washington Department of Labor and Industries is conducting a separate investigation.

No timeline has been announced for the completion of either investigation.