Don’t worry about that loud siren that might be heard across Goleta and Isla Vista this morning; it’s just an annual test of the warning system at an oil facility near Ellwood Mesa.

Venoco Inc., an oil company that owns rigs in the Santa Barbara Channel, will be conducting a full siren test at its Ellwood Onshore Facility for one to two minutes at 9:30 a.m. Santa Barbara County Fire Department Dept. spokesman Diondray Wiley said the test is of an emergency alert system that could potentially warn residents in the area of dangerous gas leaks. Wiley said the siren will be heard primarily in the Winchester Commons area near Ellwood, though Isla Vista residents may hear the sirens depending on weather conditions. The Ellwood facility separates crude oil from water and processes natural gas.

According to a Venoco flier about the drill, the mandatory coverage area for the siren is identified by signs. The area includes Calle Real, roughly from the entrance to the Embarcadero Municipal Improvement District east to the Cathedral Oaks intersection. Parts of Hollister Avenue east of the Bacara Resort and Spa tennis courts to just past the Sandpiper Golf Course Club parking lot are also in the coverage area.

Wiley said that if a leak from the facility were to occur, it would most likely be of hydrogen sulfide – which could kill a person if he or she were sufficiently exposed to it. He said such danger makes it essential that the facility has a functional siren system.

“[The siren test] is supposed to alert the people in the area that they need to get out of the area,” Wiley said.

Wiley said last year’s test occurred right after an actual leak of an odorant usually added to gasoline, causing confusion as to whether residents should evacuate.

“Last year they had an accident a minute before the sirens, so some people thought it was just the sirens test,” he said. “We’re hoping this year nothing like that happens and it’s just a planned drill.”

Though no action is required today by anyone who hears the test, according to the Venoco flier, on any occasion that the alert system goes off that is not a drill, people parked in cars should stay in them with the windows rolled up, vents and engine off and the radio on to listen for instructions. Those driving in cars should turn off the heater or air-conditioner and drive out of the area, while those riding or walking in the area should simply proceed away from the facility. People in their homes do not need to take any action apart from staying away from the facility until the siren stops.