Update 4:51 p.m.: This story has been updated to include information about the Dallas school district.

Texas is failing students by not doing enough to protect them from dangerous levels of lead in drinking water, representatives from environmental groups said Thursday.

Nearly two-thirds of the 500 North Texas-area schools whose water quality is readily available have lead contamination, said Bay Scoggin, director of the Texas Public Interest Research Group. Statewide, about 70 percent of all schools tested have shown lead, the group found.

“We can do better than that,” said Scoggin, standing outside of Dallas’ Bryan Adams High School.

Scoggin praised the Dallas school district for voluntarily testing their water regularly and taking action when results show lead levels above 15 parts per billion. But he pointed out that the federal Environmental Protection Agency has stated that there's no safe level of lead.

Adams, for example, had results showing as much as 13 ppb at the school, Scoggin said.

The EPA generally requires action if levels are at least 15 parts per billion, or ppb, in water though schools typically don’t have to meet that standard and aren’t required to test.

The environmental groups urged lawmakers to pass a bill by James Talarico, D-Round Rock, that would define an elevated level as 1 ppb in Texas and would require, among other things, that schools and childcare facilities have a plan of action to prevent and address lead contamination.

“No parent should have to worry about their child drinking from a school water fountain,” Talarico said in a statement issued about his bill.

Across the country, schools and cities have struggled with aging infrastructure and equipment that contribute to high levels of lead. Water quality concerns rose after the crisis in Flint, Mich.

Research has shown prolonged exposure to lead can have serious health effects, particularly in brain development among children.

In 2016, the Fort Worth school district found widespread problems of lead in dozens of its schools. Many districts across the state, including Dallas, soon began testing as well.

DISD and other districts have replaced equipment, added filters for water fountains and used other types of retrofitting to address elevated levels of lead when they were found. But the advocates said the threshold for action is too low.

Molly Rooke, a volunteer with the Dallas Sierra Club, urged Dallas ISD and other districts to be more proactive in replacing and retrofitting drinking fountains and water sources used for cooking in schools.

“Let’s stop waiting for tests to confirm that our children have been drinking water laced with lead and, instead, take immediate steps to get the lead out,” she said.

Meanwhile, Dallas school officials say they are trying to be strategic in their approach. Scott Layne, deputy superintendent of operations, said DISD tested all its facilities from 2016 to 2018. About a dozen schools had issues that were addressed, Layne said.

The district will resume testing again this summer. Layne said the goal is to get on a testing schedule where each school is tested at least once every three years.