The Center for Disease Control and Prevention is urging military families who have lived or worked at Camp Lejeune to take a health survery about contaminated water at the base.

They posted these public service announcements on YouTube. The agency has sent out nearly 300,000 surveys so far and received more than 63,000 responses. The deadline is Dec. 31.

Health officials believes as many as 1 million people might have been exposed to tainted water before wells were closed more than 20 years ago.