SACRAMENTO (CBS13) – A hazmat crew from the Sacramento Fire Department responded to a situation in Sacramento on Tuesday.

The incident happened in the 2100 Block Evergreen Street, just south of Arden Way. Seven Caltrans workers complained of respiratory irritation after being exposed to a powdery substance that was released into the air, according to a statement from the Sacramento Fire Department.

The workers were treated and released at the scene. Evergreen Street was closed in both directions south of Arden Way while the substance was identified and cleaned up.

Several homeless encampments downwind from the area have been evacuated as a precaution, the fire department says.

A fire department spokesperson says the origin of the material is under investigation.