MARTINEZ -- The Contra Costa County Community Warning System will conduct telephone emergency response tests Wednesday night.
The test phone calls will go to residents who live near four refineries and chemical plants and those who have registered to receive the county's emergency alerts.
According to a news release, the dry run aims to test " ... a potential new emergency telephone notification service provider to determine its call capacity and quality."
The county's emergency alert system was widely criticized after failing to promptly reach thousands of area residents on Aug. 6, 2012, when a crude unit in the Richmond Chevron refinery went up in flames and sent smoke pouring across the East Bay.
Residents living in communities surrounding the Chevron refinery, the Shell refinery in Martinez, the Phillips 66 refinery in Rodeo and the Dow Chemical facility in Pittsburg will receive calls.
Richmond's test call will begin at 7 p.m., while the others will occur between 5:30 p.m. and 8 p.m.
County residents may sign up for the alert at www.cococws.us.