Nearly 450 workers at five nursing homes in Hartford, Rocky Hill, West Hartford, Bloomfield and Windsor will begin a strike April 22 to resolve what they describe as unfair labor practices, their union announced Tuesday.

“Many of the caregivers, dietary, housekeeping and laundry workers we represent have received poverty-level wages, have spent weeks or days without pay, and have worked in some cases 16 hours a day for weeks on end,” said Jesse Martin, vice president of SEIU District 1199 New England.

The union announced that its membership had overwhelmingly authorized a strike for April 22 starting at 6 a.m. at Bloomfield Health Care Center, Hebrew Center for Health & Rehabilitation in West Hartford, Maple View Health and Rehabilitation Center in Rocky Hill, Windsor Health and Rehabilitation Center and Avery Heights Senior Living in Hartford.

“These employers have committed significant violations of federal labor law,” Martin said. “In one case at Windsor Rehab, they hired unlicensed staff, required them to work for two to three weeks without wages in exchange for the employer possibly taking the CNA licensure — this is modern day slavery.”

The union said those nursing homes are also among the last stragglers to reach new labor contracts; it said it has successfully negotiated multi-year agreements with about 90 percent of Connecticut’s nursing homes.

It wants minimum wages of $20 for certified nursing assistants, $18.50 for other workers, more affordable health insurance, retirement and pension contributions, and what it called measures to address racial discrimination.

National Health Care Associates, which owns the nursing homes in Rocky Hill, West Hartford and Bloomfield, countered that it has been bargaining in good faith all along.

The company has agreed to increases of 15.5 percent to 20.5 percent for minimum wage employees starting next summer, and a 4.5 percent raise for anyone earning more than minimum wage, it said.

“We also have committed to using monies from the state to fund a defined contribution employer pension plan, and to make improvements to the health plan and/or make it more affordable,” spokeswoman Christina Fleming said in a written statement.

“By contrast, the union made an initial proposal on Feb. 21 and, with one exception, has not modified its position,” Fleming said.

National Health Care will continue negotiating and believes a strike isn’t the right answer, she said, but added it is “doing everything necessary to limit disruption to our residents and ensure patient care is in no way affected.”

At Avery Heights, Administrator Bill Thompson offered a similar response.

“We will continue to negotiate in good faith in hopes of reaching a settlement that is fair and equitable to the team members represented by NEHCEU,” he wrote. “If no agreement can be reached before the April 22nd deadline, Avery Heights will continue to ensure the ongoing care, safety and wellbeing of our residents.”

Windsor Health and Rehabilitation did not respond to a message Tuesday.

The union said its members have filed grievances and that at least 10 National Labor Relations Board complaints are pending, but claimed it must strike to prevent further losses to workers.

It said some members have been threatened and harassed for union membership, and that some of the nursing homes have refused to pay new employees for their first two or three weeks of work.

As part of a COVID 19 mitigation package, the companies all received state aid to help pay workers - but some have refused to spend it even while they’re shortchanging employees, Martin said. He said the union is concerned that when the state department of social services audits those grants, it will reclaim the money and the workers will never get what they’re owed.

Several certified nursing assistants from the homes attended the morning press conferences at 1199′s Hartford office, and told of long-time workers still making substandard wages - despite the demands of the pandemic and the shortage of health care workers.

“We have worked consistently and are tremendously tired through the COVID (pandemic). We should be paid fairly for the work we have done and are still doing,” said Annamaria Parsons, a CNA at Avery Heights. “The boss is making lots of money and doesn’t want to share.”

Yvonne Foster said she has worked at Windsor Health for 21 years and still doesn’t make $20 an hour, has no retirement account and can’t afford health insurance.

Marcia Armstrong, a CNA at Bloomfield Health, said coworkers who’ve put in 30 and 40 years are being treated unfairly, and accused her employer of making promises that go unfulfilled.

“We’ve been told for two years that we’re essential, yet I still can’t pay my bills or afford health care with the low wages I’m being paid,” Nadine Lawrence, a CNA at Bloomfield Health Care Center, in a statement. “I’m at my breaking point.”