“The Foundation relies on a system of labor that has historically undervalued its workers, paying workers minimum wage without benefits or basic protections,” the employees wrote in the statement.

The museum responded to the filing by saying in a statement that it highly values the work by the associates and looks forward to learning more about their requests. “As an organization,” the museum said, “we are supportive of all recommendations to improve the workplace experience and will give this careful attention as we begin our discussions.”

There has been a recent uptick in labor organizing at American museums and employees at the New Museum and the Guggenheim in New York, and the Frye Art Museum in Seattle, have voted to form unions in the past year.

Maurice and Paul Marciano founded Guess in 1981 along with two other brothers and succeeded with a business model that transformed dungarees, a utilitarian worker’s garment, into a fashionable and pricey item.

The brothers became well known as art collectors in Los Angeles, where Maurice served on the board of the Los Angeles Museum of Contemporary Art for several years. He is now chair emeritus.