What to know about the water tank caps that went up in Washington state

Washington state officials are trying to find out what caused thousands of water tanks to burst into flames, prompting a state of emergency.

The Washington State Department of Ecology says in a news release that water tanks are not permitted to have more than 10 gallons of water on them.

But, it adds, the water tanks were likely leaking.

The fire broke out Thursday at a water tank in the city of Lynnwood.

The agency says it is investigating whether the cause was an electrical failure.

Officials are also investigating if the incident was caused by a malfunctioning or faulty device.