In August, hundreds of actors excoriated the health plan of the American union for professional television and film actors for changes that would result in some members no longer qualifying for health insurance, because they were unable to work during the pandemic.

Now, 10 participants in the plan are suing, in a class-action filing.

Ed Asner, a 91-year-old seven-time Emmy winner, and nine other participants in the SAG-AFTRA Health Plan filed a lawsuit in federal court in Los Angeles on Tuesday objecting to benefit cuts and changes in eligibility requirements in the plan that are to take effect on Jan. 1. The SAG-AFTRA Health Plan and its trustees are named as defendants.

Mr. Asner, who is the lead plaintiff, is a former SAG president and a current member of the SAG-AFTRA national board. He will lose his coverage when the changes take effect because he will not reach the new qualifying earnings threshold, according to the lawsuit, which claims the cuts “wrongfully and illegally” discriminate based on age. (Members who are 65 or older will no longer be allowed to use their residuals income to qualify for the new threshold if they are taking a union pension.)

The lawsuit claims two counts of breach of fiduciary duty, and one count each of engaging in a prohibited transaction and failing to disclose information material to plan participants.

“Far less draconian and equitable adjustments were available for a one-time event like Covid-19,” according to the lawsuit.

Many performers are facing a loss of health care coverage at a time when film jobs are scarce and live theater is almost completely shut down. The health insurance fund that covers stage actors announced changes in October that raised the number of weeks they would need to work to qualify for coverage, and Local 802, the musicians’ union, has started a #SaveNYCMusicians campaign aimed at shoring up the union’s health fund, which is financed by employer contributions.

The lawsuit seeks financial damages, and to wrest control of the health plan from the trustees and appoint an “independent fiduciary” to manage it and potentially reverse the changes.

On Tuesday, more than a dozen high-profile actors, including Mark Hamill, Whoopi Goldberg and Morgan Freeman, criticized the upcoming benefit cuts for seniors in a video released by the SOS Health Plan, a group of SAG-AFTRA members opposed to the Health Plan changes.

“Why isn’t the union fighting for me?” Ms. Goldberg asks in the video. “I paid into the health plan for my whole career,” she says, adding that she was very angry.

A spokeswoman for the SAG-AFTRA Health Plan did not respond to a request for comment on Wednesday.

In August, the health plan had said in an email to members that it would raise the floor for eligibility to those earning $25,950 a year, from $18,040, effective Jan. 1, and that premiums would also increase. According to the email, the changes were in response to projected deficits of $141 million this year and $83 million in 2021.

Nearly 20,000 people have signed a petition asking the health plan to reverse the changes.

“Every actor in America is stuck right now,” John E. Brady, a film, television, and commercials actor who has been a union member for more than 30 years, told The Times in August.