State of emergency declared in Southern California

California lawmakers and the governor are now appealing to the White House to make a disaster declaration.Authorities say they are making progress tonight and may be able to avoid a catastrophic disaster.There is desperation to find a solution to this crisis.The tank is located in a densely populated area just miles away from two Disney theme parks, Angel Stadium and Knott's Berry Farm.At least 50 ,000 people in Orange County have been forced to evacuate their homes and seek residence in temporary shelters.And the mayor is warning residents not to ignore those evacuation orders, calling this a very dangerous situation.

ABC's Jacqueline Lee leads us off from the command center.

Tonight, progress in the desperate efforts to prevent an environmental disaster in Orange County, California.Crews able to get close enough to that unstable 7 ,000 gallon tank full of hazardous liquid, finding a potential crack, offering a glimmer of hope.Why would this be a good thing?

So the thing about the crack is what we're looking for.It's going to relieve pressure.We want the pressure relieved out of that tank.

He goes on to explain there could still be an explosion, just not a catastrophic one.For days, officials have feared the tank would either explode into a fireball, igniting nearby tanks, or the methylmethacrylate, a highly volatile chemical inside, would leak out.Even short -term exposure could cause skin and eye irritation and breathing problems.More than 50 ,000 residents remain under evacuation orders.Two residents filing a class -action lawsuit yesterday against GKN Aerospace, the company in charge of the tanks.And tonight, the governor requesting President Trump issue an emergency declaration to support response operations.

The EPA saying it has been monitoring air quality since Friday.

We've been involved in the modeling of different scenarios.We're being told that the tank will fail, but there are different scenarios as to what that means.

The evacuation area is a densely populated area and is not far from several major area attractions, including Disneyland, Knott's Berry Farm, and the Angels Stadium.The Angels going ahead with a game tonight against the Rangers.Officials insisting the areas outside of the evacuation zone are completely safe.Lindsay, crews will conduct another operation tonight, and if all goes well, it's possible authorities will shrink the evacuation zone.Lindsay?

So many hoping that's the case.Jacqueline, thank you.