RICHMOND — Two men were Killed Sunday in separate traffic collisions on Interstate 80, the second death happening while California Highway Patrol officers were at the scene of the initial fatality, authorities said.

The names of the men killed have not yet been released, pending notification of their families.

The first fatality happened about 3:53 a.m. Sunday in the Eastbound Lanes of Interstate 80, east of Macdonald Avenue.

A man driving a Toyota sedan collided with a guard rail causing him to be ejected, CHP Officer Adib Zeid said Monday.  The driver died on the freeway.

No other vehicles were involved.

The subsequent lane closures and resulting traffic backup contributed to the second death, which occurred less than a mile away, authorities said.

In that one, a 47-year-old San Pablo man was killed and at least three others were injured in a multi-vehicle chain reaction collision that happened about 5:55 a.m. in the eastbound lanes of I-80 near Cutting Boulevard.

Zeid said officers at the scene of the first fatality could hear the second collisions.

The CHP said five vehicles, including a Toyota Siena the San Pablo man was in, were stopped due to the fatal collision ahead of them, as well as wet weather.

The CHP said the driver of a 2015 Mitsubishi box-truck was traveling at a speed unsafe under the weather and roadway conditions and crashed into the Toyota, causing a chain-reaction of collisions.

The San Pablo man was pronounced dead at the scene.

Three occupants of some of the other vehicles were transported to hospitals for complaints of pain, the CHP said.

The box-truck driver remained at the scene and was cooperating with investigators.

The CHP said drugs or alcohol are not suspected to have been factors in what happened.

No citations were issued or arrests made, pending the outcome of the investigation.

Anyone with information about the collisions may call the Oakland CHP office at 510-457-2875.