Three African-American construction workers said this week that they were targeted by racial slurs and death threats, including black dolls hanging from nooses in the bathroom, while working on the site of a San Francisco high-rise.

The workers, Craig Ogans, Douglas Russell and Don’ta Laury, filed complaints Thursday with the California Department of Fair Housing and Employment against Clark Construction, based in Maryland. The company is building the 43-story tower where the men worked. Facebook is expected to be its major tenant.

The three men were elevator operators on the site in the city’s financial district. Their complaints said they were repeatedly harassed and discriminated against by co-workers, including a threat with a knife, as part of a concerted campaign to drive them off the project.

“It made me feel hurt, angry, scared, fearing for my safety,” Mr. Ogans said in a phone interview. “It was an emotional roller coaster for me.”