"I was hazy, having coffee," he recalled. "I hadn't looked at the TV. They said, 'You better go turn it on.'"
Afterward the chief went about his planned schedule, interviewing applicants for jobs at the dispatch center, but, "It was a weird, weird day," he said.
It was Tuesday, Sept. 11, 2001.
Six days later he and the 66 other emergency responders of California Urban Search and Rescue Task Force 3 were at Ground Zero in New York City, trying to grasp the magnitude of the attack.
Ten years hasn't dimmed the pain. Or the pride.
The task force knew going in that they weren't looking for survivors, or even anything recognizably human. The collapse of the Twin Towers pancaked 70 stories of reinforced steel into a 70-foot basement, grinding bodies into the very dust the responders were breathing.
Shirley Hammond and her Doberman, Sunny Boy, began searching portions of the site. Trained to track the living, Sunny had nevertheless acquired an ability to find cadavers. One day, a New York City chief asked for a dog-handler team to search a specific location, and Hammond responded.
"There were four fellows with torches cutting beams," Hammond recalled. "I assumed they were firefighters, searching for one of their own. Sunny kept returning to one area and finally pawed a spot on the ground."
Later one of the firefighters came up and put a hand on her shoulder.
"He said, 'It was our brother,'" Hammond, a search-and-rescue veteran, recalled after pausing for several moments to regain her composure.
There were living victims, however — the responders themselves.
"Our job was not just to rescue people but to rescue their psyches," Greene reflected. "We're not just using our fancy tools for recovery. Our job is to rescue the survivors."
California Task Force 3 wasn't immune to the mental strain. Shortly after arriving in New York, some of its members were dispatched to form a rapid-response team in case other attacks followed. The hairs on Chief Harold Schapelhouman's arms stood up as he talked about learning that the emergency responders were expected to be targets. Without telling their families, the team took DNA swabs of themselves. For identification. Just in case.
And despite the overwhelming emotional support given to the responders, some moments still stung.
"What makes it hard is when someone's outside the site, holding up a photo of their loved one, and knowing that's not what you found — you don't want them to know what you're dealing with. And the pull is to give them what they want; you have to get over it," Schapelhouman said.
The lessons that guided the team in New York were learned the hard way, at the site of the Alfred P. Murrah Federal Building bombing in Oklahoma City in 1995.
Both sites were graveyards, Schapelhouman said, but Oklahoma was "a little house of horrors." In New York City, remains were recovered using "little red biohazard bags. In Oklahoma, we used body bags."
As others searched for remains, Dave Hammond, Shirley's husband, used his engineering expertise to keep the federal building from falling down while other responders were taking it apart.
That experience stood him in good stead in New York, although the World Trade Center presented different challenges.
"The most dangerous thing about that site was the footing, and the chemicals," he said, then held up a photo of the debris. "The biggest thing for an engineer is getting your mind around what it is. The first thing you say is, 'Oh ----.' Then your training kicks in."
After Oklahoma, Hammond said, he would wake up at night, rocking back and forth in bed. Being on the periphery in New York, the sheer, unthinkable scale of the destruction made it easier to cope.
Some reminders of 9/11 are physical rather than psychological. At a reunion held about a month after the team's deployment, the task force began realizing that 70 percent of their members had gotten sick, according to Schapelhouman. Pneumonia in 20-year-old firefighters; lingering coughs; skin rashes; inexplicable nose bleeds. To this day, the chief struggles with the aftereffects.
"I'll never regret going to New York, but part of what I wish I could undo is not wearing a mask because I was on the phone, on the radio," he said. "When I get sick now, I get really sick."
The Centers for Disease Control and Prevention eventually established a health support program for 9/11 responders.
On the fifth and 10th anniversaries of Oklahoma City, task force members traveled to the site, which Schapelhouman said was critical in allowing him to move forward.
"I saw a kid, maybe 1 or 2 years old, playing in the (memorial) reflecting pond and I realized he didn't know what it was," he said. "It symbolized that I had to let it go."
The same realizations for 9/11 might be harder to come by. The 10-year memorial in New York City this year excludes the responders, for reasons ranging from expense to security, according to the chief, who has held off on sending a letter of protest to the mayor in hopes that the decision would change.
"What's missing here is the deeper level of significance. Why not allow them to come in, let them try to find that closure?" Chief Schapelhouman said.
Closure or not, Sept. 11 will never again be just another day for those who responded to Ground Zero.