Originally Published: 30 OCT 23 12:19 ET

Updated: 30 OCT 23 14:11 ET

By Nicole Goodkind, CNN

New York (CNN) — Employees at some of the largest drugstore chains in the United States are staging a new series of walkouts across the country Monday to demand the companies fix what employees say are harsh working conditions that make it difficult for them to safely fill prescriptions, and which could put the health of their customers at risk.

Walgreens and CVS employees are mostly not unionized, which makes a largescale walkout difficult to execute. Staff and organizers in multiple states confirmed to CNN that the walkouts have begun and will take place through November 1, but it remains unclear how widespread the action is.

Workers at Walgreens and CVS have previously staged walkouts in Arizona, Washington, Massachusetts and Oregon in September and early October. Those work actions closed a handful of pharmacies briefly, and slowed business at several others. At the time, Walgreens told CNN the impact has been “minimal.”

Shane Jerominski, an independent pharmacist in Southern California who used to work for Walgreens and is one of the walkout’s organizers, told CNN on Monday that organizers are already overwhelmed by calls about closed pharmacies.

During prior walkouts, pharmacy staff feared retaliation from their bosses and corporate leadership, said Jerominski. But there was no reported reprisal from leadership, which, he says, has emboldened more staff to participate. However, some employees who may still be concerned about a company reprisal are calling out sick instead of walking out, he said.

As of early Monday afternoon, Jerominski says he doesn’t have an exact figure for how many stores or workers have participated in the job action. But he told CNN that he expects momentum to build over the next three days and the largest day of action to be Wednesday, when a demonstration in Chicago is planned to take place.

He says representatives from unions are helping to plan the walkouts which were specifically scheduled to begin the day before Halloween because it’s a particularly busy time for pharmacy chains as cold and flu season begins and demand for vaccinations soars.

A spokesperson from the United Food and Commercial Workers International Union (UFCW) told CNN on Sunday that it supports the organizers planning a walkout and protests. The Service Employees International Union-United Healthcare Workers West also said it supports the walkout and protests.

“UFCW members and staff have been communicating with many of the CVS and Walgreens workers who have been taking actions to stand up for their rights on the job. We are the largest Retail Pharmacy Union in North America, and as such, where workers struggle, we stand ready to assist,” Dave Young, UFCW International vice-president & director of organizing, told CNN.

“Health care workers and consumers are experiencing unprecedented strain caused by understaffing by health care corporations,” Renée Saldaña, press secretary of UHW-West Health, said in a statement to CNN last week. “We support all health care workers who are organizing and taking a stance to improve staffing.”

Walgreens and CVS representatives told CNN that they haven’t seen much of a disruption to operations Monday. “We’re committed to providing access to consistent, safe, high-quality health care to the patients and communities we serve and are engaging in a continuous two-way dialogue with our pharmacists to directly address any concerns they have,” Amy Thibault a spokesperson for CVS Pharmacy said.

This is a developing story and will be updated.