Former Obama-era Housing and Urban Development Secretary and Democratic Presidential Candidate Julian Castro says more needs to be done to help communities affected by hazardous waste.

As part of his latest swing through rural Northern Nevada, Castro met with leaders from the Yerington Paiute Tribe Tuesday to discuss how that community has dealt with the groundwater contamination caused by the Anaconda Copper Mine. Some people living around the now defunct mine have elevated levels of arsenic and uranium in their groundwater, making it unsafe to consume.

The site was slotted to become a designated federal superfund site, in which the federal Environmental Protection Agency would oversee clean-up efforts, but has since been given to the state to manage. Castro says the federal government could do more to help communities affected by the hazardous waste left behind by industry.

“We have so many superfund sites already identified and then a lot of them, a lot of sites that may not be designated superfund sites but should be," Castro said. "So, in the years to come, we’re going to have to hold that private sector more accountable and also dedicate more public resources to remediating superfund sites.”

In addition to the town hall with native leaders, Castro also spoke to voters in Douglas County. The Texas Democrat, who has so far had a lackluster result in polling, has made Nevada a critical part to his campaign.