CHARLESTON, W.Va. (AP) _ Federal officials say studies reinforce advisement that people could use tap water shortly after a chemical spill in West Virginia last year.

The National Toxicology Program on Tuesday evaluated updated findings about the chemicals that spilled.

Some studies used pregnant rats, zebrafish and nematoads. Others used cellular, molecular and computer modeling to identify potential health effects.

State Health Officer Dr. Rahul Gupta called the results reassuring.

The January 2014 spill in Charleston tainted water for 300,000 people. Using limited research, federal officials quickly crafted a standard about when water was safe to use again. A ban was lifted after four to 10 days.

Still, people visited hospitals with symptoms from rashes to nausea.

Advocacy group People Concerned About Chemical Safety said questions remain, including effects of inhaling the chemical vapors.