INDIANAPOLIS (AP) — An expert on the nation’s coal ash ponds will address Indiana environmental advocates during their annual gathering focusing on the state’s upcoming legislative session.

Earthjustice attorney Lisa Evans will keynote Saturday’s “Greening the Statehouse” event that the Hoosier Environmental Council is hosting at the University of Indianapolis. She’s a coal ash expert with 25 years of experience in hazardous waste law.

Coal ash is the waste left when coal is burned to generate electricity. It contains heavy metals such as arsenic and mercury.

Hoosier Environmental Council Executive Director Jesse Kharbanda says Indiana has more coal ash ponds than any other state, with 84 statewide, according to a report the group released last year.

That report also found Indiana’s electric utilities produced 6.6 million tons of coal ash in 2012.