One common — and infuriating — claim made by critics of public education is that we continue to throw money down a rat hole, with little to show for it but failing students.

That's infuriating because it's not true, and it shows an ignorance about  the increasing share of education budgets that must go to rising costs over which the School District has little control. The sad reality is that in Philadelphia, the lack of money has actually created too many literal rat holes — aging school buildings that are in dangerous states of decline and disrepair because of deferred maintenance.

The Inquirer and Daily News recently conducted testing of  19 schools and found dangerous levels of mold, deteriorated asbestos, flaking, and peeling paint, likely containing lead, and water with unsafe levels of lead contamination.

The impact of these toxins is devastating and tragic on children, including cognitive and behavioral problems, as well as physical ailments, like an increase in already-high asthma rates.

According to the report, it would require $3 billion to build new schools and fix the problems at others.

This is certainly a money problem.  But it's also an equity problem: Education becomes another arena where we institutionalize the traumatic aspects of poverty, ensuring that the disadvantages poor kids start out with are not only not alleviated, but are made worse.

These troubling conditions mean we're laying waste to generations of children and families. And we're paying a steep price. The social and human costs of a hobbled generation who can't learn and can't flourish is incalculable.

But we also pay in other ways. For example, we need to acknowledge the possible links between environmental hazards and the physical and mental damage they cause, which can have a direct impact on the costs of special education, whose budgets have been rising year after year.

While many factors, like diagnosis and eligibility, contribute to the increase in special education students — now numbering 32,084 students in Philadelphia charter and regular district schools, a 17 percent increase since 2013 — it's hard not to draw a direct line between environmental toxins and the disabling impact they have on a child's growth, development, and ability to learn.

This is not just a local problem.Schools across the country are aging, though the last comprehensive look at such conditions was more than 20 years ago by the General Accounting Office. At the same time, budgets for special education are also rising across the board. In New Jersey, for example, they now comprise 22 percent of school spending, up from 13 percent in 2006-07.

Surely, we need to recognize that where we mandate our children spend a large portion of their lives should have minimum standards of safety. Yet, there is no law at the local, state, or national level that requires that schools be free of hazards. Physical maintenance must  be part of our thinking about education funding.  We can no longer insist that money be spent on instruction and technology while sending our kids to rat holes to learn.

The district — and the city, which soon will oversee the schools — are ultimately responsible for maintenance and repairs. But larger remedies must also include state and federal action.

Maintenance deferred is education — and equity — denied.