OAKLAND, Calif. -- A probe was underway Monday into the circumstances behind the death of a 77-year-old longshoreman over the weekend at the Port of Oakland after fellow employees claimed he may have drown because there were no safety ladders to reach him.

Delmont Blakeney, an Oakland resident, was reportedly trying to free a cargo container from his vessel when it broke free and knocked him into a rail, throwing him overboard just before 11 p.m. Saturday.

Blakeney remained in the frigid waters of the San Francisco Bay for nearly 40 minutes before his coworkers were able to find a ladder and pull Blakeney to shore, according to Craig Merrilees, a spokesman for International Longshore and Warehouse Union.

Blakeney was reportedly given CPR and transported to a hospital where he was pronounced dead.

"They're furious that there were no ladders and other safety equipment available," Merrilees said. "(Blakeney) was by then unconscious and could not be revived."

The port workers said they are especially angry because earlier this month, another longshoreman fell into the waters and had to wait for nearly an hour while colleagues searched for a ladder to rescue him, according to Merrilees.

"Just weeks before, a longshoreworker was thrown into the water and had his arm broken when a line securing a ship suddenly snapped," Merrilees said. "The worker struggled in the water for nearly an hour because there was no safety equipment, in particular a ladder, nearby to rescue the man."

Merrilees said the docks are "high above the water" and it is impossible to climb ashore from where the men fell.

The International Longshore and Warehouse Union is comprised of more than 1,000 workers, all of whom did not work today in response to Blakeney's death, according to Merrilees.

Port of Oakland officials said they will be investigating what happened regarding Blakeney's death.

"As a landlord seaport the Port of Oakland is concerned about safety," Port of Oakland spokeswoman Marilyn Sandifur said. "We will be checking into this incident with the Pacific Maritime Association and the terminal operator to find out what happened and what steps they could take to prevent this situation from happening in the future."