As a public service, The Inquirer is making this article and other critical public health and safety coverage of the coronavirus available to all readers.

In an email to customers last week, Santander Bank noted it was “reverting back to traditional disinfectant cleaning products from the green products being used today until further notice to maximize the effect of the cleaners.”

It’s not easy being green right now.

Faced with the new coronavirus, an enemy we can’t see but that we’re told might, like similar viruses, be able to live on some surfaces for up to several days, what seems natural is to reach for the biggest weapons in our arsenal.

Which could explain why, when I went to buy disinfecting wipes a couple of weeks ago at Wegmans, the shelves were bare of all but those made by Seventh Generation, a pricier brand that markets itself as eco-friendly. The label boasts of its ability to kill “99.99% of bacteria & viruses,” but when I got it home, I noticed its active ingredient, thymol, was one I’d never heard of.

The liquid soap aisle told a similar story. Largely empty shelves, but plenty of the more expensive Mrs. Meyer’s, which advertises that its products aren’t tested on animals and that they “never contain ammonia, chlorine, parabens, phthalates, formaldehyde, artificial colorants, phosphates or petroleum distillates.”

But what if we think we need some of those very things right now? And what about people who’ve long sworn by basics like vinegar and baking soda to clean their homes?

Eric J. Beckman is most concerned about the latter group.

What vinegar and baking soda do, “and the only thing they do, is they change the pH,” said Beckman, the George M. Bevier Professor of Engineering in the chemical engineering department of the University of Pittsburgh. Vinegar is a mild acid and baking soda a mild alkali. There’s no evidence that either is effective against viruses.

“Viruses are robust creatures,” he said.

Which doesn’t mean they can’t be killed by something short of a flamethrower. According to Chemical & Engineering News, “there’s good evidence the novel coronavirus is one of the easiest types of viruses to kill.”

We talked to Beckman about what works against viruses.

Here’s what to know:

  • Soap is awesome against viruses. All kinds of soap. So keep washing your hands.
  • Nothing’s faster than bleach, particularly chlorine bleach, on surfaces. “Either chlorine bleach or OxiClean … which is a hydrogen peroxide derivative,” Beckman said. "What bleaches do is they’re like molecular garden shears. They just chop things up.”
  • The biggest downside to chlorine bleach, besides the smell? “It’s an energy hog. It’s estimated that 1 to 2 percent of the world’s electricity goes into making chlorine.”
  • If your yen for virus-killing power outweighs your green leanings right now, one ingredient to look for is quaternary ammonium, found in Lysol, and in a number of other products.

While noting that the list may not include all disinfectants that meet its criteria, the Environmental Protection Agency offers a searchable list of products that so far are allowed to claim — though not yet on labels — that they can be expected to do the job. That’s based on their performance against viruses similar to the new coronavirus.

Such viruses, wrapped in a fatty coating, are considered more vulnerable than some others. "It’s sort of a wimpy protective shell,” Seema Lakdawala, a virologist at the University of Pittsburgh, told Chemical & Engineering News.

How green can you go?

Green light: Handwashing. You can use any soap, green or not, to wash your hands. As long as it sudses for 20 seconds, it will do the job.

Yellow light: Think twice about cleaning surfaces with products that aren’t advertised as disinfectants or as killing viruses, which many eco-friendly products might not be. Soap in those products doesn’t work as fast as bleach, hydrogen peroxide, or alcohol.

Red light: Vinegar and baking soda are no match for viruses.

How soap works

Soaps are either ionic or nonionic, with the ionic ones being more efficient and the nonionic ones easier on the skin, Beckman said.

The ionic ones in particular, if you looked at them, “they might remind you of a sperm,” with a small head — “that’s the ionic part” — that loves water and a tail, “which is a fatty chain, that loves oil.”

All soap, he said, “blows up” the cell membranes of viruses. “People say over and over again, ‘Soap, wash your hands, wash your hands.’ And it sounds like they’re just being a scolding second grade teacher. But there is a rationale behind it. Soap does a job on cell membranes, and we’ve known that for a long time."

Evaluating three popular green products

Beckman, who’s also codirector of Pitt’s Mascaro Center for Sustainable Innovation, walked me through the labels of a few popular products, including Tom’s of Maine hand soap, Mrs. Meyer’s Clean Day Basil Scent Multi-Surface Everyday Cleaner, and those Seventh Generation wipes I’m still using at home to wipe down doorknobs and counters.

Looking over the ingredient lists of all three products, he spotted soap in places I saw only gibberish.

Tom’s of Maine hand soap includes two soaps: caprylyl/capryl glucoside and decyl glucoside.

Mrs. Meyer’s surface cleaner also has decyl glucoside, a surfactant Beckman described as gentle and degradable, as well as lauryl glucoside, another degradable, nonionic soap. Skipping ahead on a list of Mrs. Meyer’s ingredients, he singled out sodium methyl 2-sulfolaurate. "Now that is an ionic soap. So that thing will do a job on anything with a cell membrane,” Beckman said. “It just blows up cells, and it will do the same to viruses.” (Mrs. Meyer’s doesn’t, however, claim to be a disinfectant.)

And what of my Seventh Generation wipes, which are labeled as killing, among other things, the H1N1 flu virus? And what’s thymol, anyway?

“Thymol is a naturally occurring antibacterial,” Beckman said, adding that he hadn’t personally seen any research about its effectiveness against viruses. However, the Seventh Generation label also lists sodium lauryl sulfate. "That is a classic ionic soap. So if the thymol doesn’t get it,” the soap will, he said.

“I think you’re fine.”