FINAL UPDATE: PG&E ended the alert at 6:45 p.m. on Friday night, saying air quality in the affected reactor was restored.
UPDATE 7/28/17 3:20 p.m.: The county's emergency operation center says "the plant is in a safe condition and remains at full power. There is no radiological release at this time."
Decreased oxygen levels in one of the plant's reactors prompted PG&E to declare an alert at Diablo Canyon Power Plant just after noon Friday. According to the company, there is no risk to the public or employees at the moment, but the county has activated its emergency operations center.
An initial news release issued by San Luis Obispo County Emergency Operations Center said the alert was declared "based on a non-radioactive gas release," in an area of the plant.
Two hours later, a second county news release said the alert was prompted by another reason.
Oxygen levels in the Unit 2 reactor had decreased, although the company said both of the plant’s reactors are “in safe condition and remain operating at full power.”
In an emailed statement, PG&E said the alert was activated “because personnel who may need to access this area of the plant would potentially need to use additional breathing apparatus to enter containment during an emergency to operate equipment. Once operators restore Unit 2 containment oxygen levels to above 19 percent -- from the current level of 18.5 percent -- and county key stakeholders agree, the alert declaration will be lifted.”
KCBX News will update this post as more information becomes available.