Phase 2 of Massachusetts' re-opening is underway, and companies and businesses are working to clean and disinfect workspaces as employees return. But businesses also face a whole new world of rules and safety precautions to keep people safe from the coronavirus, prompting many to turn to a process called “deep cleaning.”

Deep cleaning is usually done by professional cleaners who use a machine that sprays cleaning agents that sanitize and disinfect.

“We call it ultra clean or ultra-spray services,” said Cintas Boston General Manager Scott Lee. Cintas is a 100-year-old, Fortune 500 company that does deep cleaning.

Lee said workers wear the spray machine on their backs, or they roll it beside them on the floor, spraying EPA- and CDC-approved cleaning agents directly onto surfaces. Desktops, break rooms, locker rooms — Lee said all of it gets sprayed down.

“The easiest way to think of it is basically like a backpack — like you would see a pest control or somebody have," Lee said, "except instead of spraying pest control products, we’re spraying disinfect and sanitizer.”

Lucille Ward is human resources manager with Package Steel Systems in Sutton, Mass., which manufactures steel across New England. It’s considered an essential business with almost 50 employees that work in its industrial plant and an office. To keep them safe, Ward has used Cintas to deep clean during the pandemic.

“So, we brought in a cleaning and industrial company that cleans plants and stuff like that because it's really dirty up there," she said. "It's a fabricating shop.”

Ward's company follows a cleaning regiment recommended by the Associated Industries of Massachusetts, AIM, a 3,500-member advocacy group of employers.

Thomas Wesley is senior director with environmental health and safety, real estate, and sustainability with the Waters Corporation who serves as chair of the AIM’s re-opening task force. He helped write an 80-page handbook for employers called, “The Return to the Workplace Guide.” It contains guidance and checklists businesses can use as they welcome employees back to work.

The guidance complies with state and federal regulations, and it follows Governor Charlie Baker’s state-mandated re-opening workplace practices.

Wesley said it’s important for customers and employees to feel safe. For example, businesses need to provide enough room for social distancing and have ample supplies of personal protective equipment. Other protocols include sanitation supplies and hygiene stations. The goal is to have cleaning become part of employee’s routines.

“And so, if you don't have the environmental piece squared away,” Wesley said, “if they don't feel as though it's a safe environment and that you have a cadence to your routines that ensure the safety of the workplace, that's where people are going to get skittish about coming back.”

Marcello Tolentino of Boston’s Best Commercial Cleaning knows all about the safe return to the workplace. He said that when the pandemic hit things changed dramatically, and most clients asked for deep cleaning.

“When everything started, they decided to have like a deep cleaning,” Tolentino said, “what they call a deep cleaning or disinfecting. “

That also means paying close attention to those “high touch” places such as doorknobs, handrails, doors, windows and elevator buttons.

Deep cleaning also relies on trusted disinfectants and sanitizers — sanitizers lower the number of germs to a safe level, while disinfectants kill almost all germs

“There's no current claim on killing COVID-19, because there's not enough information," Lee said. "But our disinfectant has a kill claim on SARS [and] COV-2, which we believe is very similar. But we can't make the claim that we can kill COVID-19. No one can. If they do, it's an accurate at this point because there’s not enough testing."

The "deep cleaning" spray machine that professionals use goes onto surfaces wet, and it dries in about 10 minutes. But Wesley says there’s one thing that a dep cleaning machine can’t do.

“No matter who you're talking to, whether it's the [World Health Organization], with the CDC, or any government authority, the most effective way of avoiding contracting this virus — this is the hygiene element to this — washing your hands regularly.”

Treating surfaces with special spray machines, scrubbing and sanitizing high touch points — it’s all key to keeping the virus out of the workplace. But nothing beats a good old-fashioned hand washing.