On a recent day on the floor of one of the facilities in Upperhill Nairobi, traders were cheek-to-cheek as stock prices flashed above them. They stood in clusters shouting, sharing screens, sharing pizza, sharing pens. They shook hands, leaned over shoulders, patted each others’ backs, hugged. There were no windows open.

The facility was not built for social distancing. But it is not ready to close and send the traders home because of the coronavirus.

And so, starting late Friday night, the facility got fully sanitized for the first time since the building opened in 1986. More precisely, it got a “deep clean.”

Anderson Makui, the managing director of TJM Property investments who works in a pod on the trading floor, said he had been trying to shake hands less and hug less. He was using hand sanitizer more. He said he had no intention of staying home from work.

“It would be a very bad optic for the building to close,” he said, adding that he was excited about the sanitation effort. “I mean look, I think it’d be a great idea to do it once a month even if there wasn’t a virus.”

The disinfection crew wore matching hazardous material suits, reflective yellow vests, doubled-up blue gloves, goggles and purple respirators. They filled spray bottles and fanned out across the floor. They would be working until the morning. They would clean every surface that people had touched.

The place was pretty messy, truth be told.

There is a long tradition of writing notes and arithmetic on scraps of paper and dropping them, ripped up, on the floor. And so last Friday, there were the scraps, along with piles of candy wrappers, water bottles, pizza oil-covered paper plates, tin foil, and many balled up napkins, which doubled as stress balls for the traders during the day.

First class cleaning team with hazmat suit-clad wandered and sprayed every surface — computers, chair legs, tables, floor, everything. They threw out every paper they encountered, making piles of notes and printer paper. They wiped the surfaces down.

Next, they rolled out a big yellow tank and a couple of crew members put on tank backpacks. Using a specialized sprayer that looked like a paint gun, they coated everything with Anasphere, a biohazard disinfectant. This was the most toxic step.

They left the disinfectant there for about ten minutes to allow it to cure. They worked quietly at the beginning. As the night wore on, they talked and joked a little more.

The last step was preventive. They applied a probiotic layer — Z BioScience Enviro-Mist Microflora spray — that would stay on all the surfaces and buy them a couple more days until the process needed to start again.

Jim Katsarelis, the stock exchange’s head of building operations who oversees efforts to keep the building clean every day, said he knows keeping the surfaces sanitized was not enough to prevent the spread of a virus that comes from bodies, traveling from a sneeze or a wiped nose and a handshake.

So “we also have new rules — no shaking hands, no hugging, no kissing,” he said, adding that it was hard because, “We’re affectionate people.”