(CNN) When it gets too hot in Denver and Baltimore classrooms, students are sent home because their schools don't have air conditioning.
In Massachusetts, checking for rusty water leaking from a ceiling has become a "morning ritual."
In California, a school's cockroach infestation has gotten so bad that some students fear eating lunch.
While school infrastructure problems are a perennial challenge, national data and dismal stories from teachers suggest the crises are reaching an apex. Atrocious school conditions have even prompted some teachers this school year to go on strike.
"We're getting to a critical stage now," said Mike Pickens, executive director of the National Council on School Facilities. "The average age of a school building now is from 49 to 50 years" -- the highest in memory. Some schools date back to World War II.
But as schools get older and more desperate for repairs, the funding gap for public schools keeps getting worse.
"American Society of Civil Engineers gives the condition of America's 100,000 public school buildings an overall grade of D+," the National Education Association said late last year. "And no wonder -- half our school buildings are half a century old."
Now, everyone is paying the price for underfunded schools.
Students get sick, distracted or miss entire days of education when conditions turn abysmal. Parents sacrifice income to provide child care when classes suddenly get canceled.
Burnt-out teachers already stressed by the pandemic and school violence are pushed closer to leaving the profession.
Even those not directly connected to deteriorating schools will be impacted, Pickens said.
Without more investment in US public schools, he said, "we get further and further behind on the world stage."
In Baltimore, Marcia Turner is sick of her kids feeling sick at school.
"My children can't even breathe in the school. It be so hot. One have asthma," Turner told CNN affiliate WMAR.
Fourteen Baltimore schools don't have any air conditioning, school district Chief Operating Officer Lynette Washington told CNN. Those students get sent home early when it's too hot to learn -- 85 degrees or higher in their classrooms, she said.
Stifling temperatures can impede students' academic success. Researchers who looked at millions of test scores from American high schoolers found students tend to score lower when it's a hot school year, according to a 2018 study published by the National Bureau of Economic Research.
But air conditioning mitigated many of the negative effects, the researchers found.
The lack of air conditioning doesn't just stymie students' learning. It also hurts parents who can't afford to leave work to take care of their children in the middle of the day.
"And I can't get off because I'm just starting a job," Turner told WMAR.
The Baltimore school district's COO said she's frustrated, too. About 65% of the city's public schools are over 41 years old; more than a third are over 51 years old.
"We have such a backlog of infrastructure that has not been updated and upgraded in a consistent way. When they're not upgraded toward the end of their life cycle, then we just hold onto them, and we just keep putting Band-Aids on them," Washington said.
"We do not have the dollars. We do not have the resources."
Five years ago, Baltimore had 75 public schools without air conditioning, Washington said. Installing AC in all those schools would cost $250 million -- about five times the district's entire annual infrastructure budget.
So Baltimore Public Schools is chipping away at the problem over years. Of the 14 schools that still lack air conditioning, six will have it in the next 24 months, Washington said. The other eight will be completely renovated -- with air conditioning -- or shuttered.
Many states away in Colorado, more than 30 schools in Denver Public Schools had to send kids home early and four closed for full days this month due to the heat, the district said. Temperatures soared in Denver the first full week of September, with daily highs ranging from 97 to 99 degrees, according to the National Weather Service.
"I can't change the fact that it's 88 degrees in the classroom," said Sara, a teacher at McAuliffe International School, which had three days of early dismissal. "It gets really draining, physically and emotionally, to be kind of beat down by these factors, day in and day out."
The middle school in Colorado's largest school district has no air conditioning, said Trena Marsal, the district's executive director of facility management. The infrastructure, she said, was never meant for higher temperatures.
"Our oldest building is (from) 1889," she said.
Forty Denver public schools still lack AC, down from 55 in 2019, Marsal said. In 2020, Denver voters approved bonds to pay, in part, for the installation of air conditioning units in schools, including a two-year plan to air-condition McAuliffe, the school district said.
But supply chain problems delayed installations this summer, leaving the work at eight schools only partially completed.
So the district has heat mitigation liaisons, Marsal said. Portable cooling units are strategically placed during the day, and windows are opened at night, she said.
Opening windows, though, means "we basically daily get wasps and flies -- and it's always exciting when that happens," Sara said.
In the heat of day, Sara said, conditions in classrooms can make older kids anxious.
"You have students, I'm sure, who are nervous about sweat stains or they sit down on a plastic chair and their butt gets sweaty," she said. "It's stuff as an adult we're not as self-conscious about, but a teenager absolutely is."
"I sweat, like, everywhere," seventh grader Zmarra Fleming told CNN affiliate KUSA. "In the classrooms, it's really hot. It's, like, hot where the point is you can't really breathe in there."
But the immediate fix -- early dismissal -- caused transportation problems this month for some students. McAuliffe got out at 1:32 p.m., according to the school's website, but Marsal said early buses weren't requested.
"It's very frustrating," parent Stephanie Bates told KUSA. "I can't imagine what parents who don't have flexibility in their schedules do."
Leaking water in classrooms and brown, stained ceiling tiles have made for a "morning ritual" among some teachers at Joseph G. Pyne Arts Magnet School in Lowell, Massachusetts.
"Outside my room, in the hallway, there's several tiles that are stained brown like rusty, dirty water from leaks," said Eric Kolifrath, a seventh and eighth grade science teacher. "Everyone on my floor, especially if it's rained, we examine the ceiling to let the custodial staff know if we see new leaks."
Last school year, a ceiling tile got so wet it "bowed out like a bowl," Kolifrath said. So custodians wheeled in a 33-gallon trash bin to collect the water.
Another time, a leak sprang right above his classroom projector.
"That's not a problem that my principal can fix," Kolifrath said. "If she had a wand, she would wave it."
That's in part because Kolifrath's school, which serves pre-K through eighth grade, and 28 others in the district are managed by the City of Lowell, which also looks after municipal buildings, City Manager Tom Golden said.
The setup is among the myriad ways American school buildings are maintained -- which can lead to confusion over who's responsible for repairs.
Like many teachers nationwide, Kolifrath has crowdsourced financial support for his classroom.
The city is putting $2.3 million into all Lowell schools during the 2022-2023 school year and investing $389 million to build a new high school, Golden said.
The roof at J. G. Pyne was repaired last year, he said. But maintaining ceiling tiles "would be the responsibility of the custodians who work for the school department," Golden said.
"With the number of buildings that we have, there are always going to be issues and challenges on a day-to-day basis, which our lands and buildings professionals will be out there to rectify."
The money spent on fixing or building US public schools falls woefully short of what's needed to get buildings up to standard, according to the latest "State of Our Schools" report by the 21st Century School Fund, the International WELL Building Institute and the National Council on School Facilities.
And the gap is widening. In 2016, public schools were underfunded by $46 billion a year (or $60 billion, when adjusted for inflation to 2020 dollars), the report said. By 2021, that annual deficit had grown by $25 billion.
"We have a gap of about $85 billion in our country from where we are to where we need to be to be current with codes and standards and the quality of education," Pickens said. "In that, $57 billion is in capital improvements, and about $28 billion is in M&O -- which is maintenance and operation."
The trend is untenable as more American schools cross the half-century mark.
Even with regular maintenance, "about 50 years is a good place to (consider) replacing a school." Pickens said.
But funding sources vary widely, and it can be hard to secure money for school improvements without raising taxes.
"Every state handles school facility improvements a little differently," said John Heim, executive director of the National School Boards Association. But "it usually comes from property taxes."
And that can put already-disadvantaged students in a more dire situation.
"It affects poor districts or those that have lower tax bases more than it does wealthier districts that have more tax base to call on," Heim said.
"And so as things get more expensive, you're going to see that gap continue to grow."
At Reading Memorial High School in Massachusetts, a longtime teacher runs up to seven fans in his classroom to try to compensate for the school's lack of air conditioning.
But those efforts don't prevent him or his students from fading as the day gets hotter.
"I don't get the same caliber of work from them as I do during those cooler months when they're actually comfortable," he said.
"I find myself adjusting my lessons as the day goes on because I know I'm not going to have the energy or mental capacity to do what I did earlier in the day because I'm so uncomfortable."
The temperature in his classroom can reach 100 degrees, and the humidity can make you "slip on the floor," the teacher said.
That's especially problematic because he has an autoimmune disease and has suffered dizzy spells that have forced him to leave the classroom to splash cold water on his face, he said.
HVAC preventative maintenance has been completed at all Reading Public Schools, the district said.
"We are committed to ensuring high quality air ventilation in all of our classrooms," Superintendent Thomas Milaschewski told CNN in a statement.
The district "will continue to encourage staff to open windows, as feasible, to increase air flow in classrooms, and to bring students outside when weather permits," the superintendent wrote.
But that brings little comfort to the veteran high school teacher -- especially because the building's central and main offices are air-conditioned, he said.
"I cannot think of many professions where people have graduate degrees or have a license where they would tolerate something like this," the teacher said. "I don't understand where the disconnect is, where you want your teachers to be the best that they can possibly be but you're not even making them comfortable."
While nonexistent air conditioning can hinder students at the beginning and end of the school year, the opposite problem can have even greater consequences.
"We tend to have to close schools down more for heating issues than for cooling issues," said Washington, the Baltimore school district COO. "Wintertime goes from December all the way up until March."
Baltimore teachers have reported classrooms as cold as 40 degrees. More than a third of the schools' boilers are over 20 years old. Some pipes were installed when Harry Truman was President.
Beyond that, one elementary school had no running water for more than two weeks last winter, according to a school district memo.
"The district is severely underfunded," Washington said.
"Baltimore's already taxed at a higher rate than the surrounding counties," she said. But "Baltimore city has a low tax base. We have a disproportionate share of households that live below the poverty line. And so if we're just depending on property taxes, we might not get there at all."
She hopes the state will increase funding for Baltimore city schools "so that we won't continue to have the infrastructure challenges that we're having."
If not, Washington said, "I cannot guarantee that our students will have the learning environments that they deserve and that they need to be successful."
Fallout from the pandemic could make infrastructure problems harder to fix this year, Pickens said.
Some school districts haven't been able to complete projects due to supply chain shortages or an increase in the cost of raw materials, he said. And remote or hybrid learning during the pandemic means some parts of schools may have been neglected.
"We've had two years of less use than we had," Pickens said. "And because students were not in buildings, we probably did not continue the maintenance and operation and capital improvements of those school buildings because students weren't in them."
Inflation this year could also be getting in the way of school improvements, Heim said.
"If we're talking about an improvement that was to be made for the 2022-2023 school year, that bid process probably would have taken place back in January, February," Heim said.
"That's when we were seeing those incredibly high building costs. And it's also when we were experiencing all those supply chain issues. So ... schools may not have been able to get the projects done in time or weren't able to do as much because of the supply chain issues and inflation issues."
Schools that aren't well-maintained can attract unwelcome visitors. Around one school building, cockroaches have occupied corners, carpets, sinks and sticky glue insect traps, an Oakley, California, high school teacher said.
The bugs can be seen every day, inside and outside the school. They grow as long as 2 inches and seem to have multiplied after school resumed in-person learning last year, the teacher said.
The infestation at Freedom High School is so bad it inspired an Instagram account. The teacher verified the cockroach photos were taken at the school and shared some personal ones from the last week of August. The teacher submitted work orders about the cockroaches in recent years but didn't report them directly to the administration, they said.
Liberty Union High School District Superintendent Eric Volta recognized Freedom High School in the social media photos, he said. The district sprays schools for pests quarterly, he said, and if there are additional needs, pest services are requested.
"We fog, we spray, we bait, we trap. We do whatever we need to do to try to correct the issue," Volta said. "We've been having triple-digit temperatures out here, and these things are coming up out of wherever they are just looking for water."
A big concern is cockroaches shed, leaving the teacher wary of eating in most places. Some students haven't wanted school lunches because of the roaches, the teacher said.
But all kitchens and snack bars go through health inspections. So Volta is not worried about the pests in eating areas, he said.
"I guess this is something that probably most teachers deal with," the teacher said.
While cockroaches might not be in every school, "there's these problems that you have that are constant, but that you just go on teaching and doing what you have to do, knowing that you almost have no control over the situation," the teacher said.
"I can keep stepping on cockroaches and killing them, but there's always more. The problem just sort of needs to be addressed instead of just putting Band-Aids on it."
And if America keeps underfunding public schools, the impact could last generations, said Mary Kusler, the National Education Association's senior director for advocacy.
"It's really setting up a continued structural imbalance between the haves and the have-nots ... unless we step up and push to ensure that a child's ZIP code does not determine the education they receive," she said.
Increasing funding for school infrastructure would "improve a lot of things in our country, including putting out into the workforce a more vibrant and more educated workforce," said Pickens, the director of the National Council on School Facilities.
"Also, by improving schools, somebody has to do the work on a school building. We're putting people to work. We're getting taxes from those people, from the labor. We're increasing jobs. All of those things are factors in providing funds for school buildings."
It's in everyone's best interest to ensure students in poorer communities have schools in which they can thrive -- even if local tax revenues aren't as plush as those in wealthier communities, said Heim, the director of the National School Boards Association.
"I think it comes down to having good formulas that can compensate for that. I think states are reevaluating those all the time," Heim said.
"But that's what it comes down to: affordability and helping those poorer districts with their facilities."
That doesn't mean wealthier school districts with state-of-the-art buildings should have anything taken away, Kusler said.
"The issue isn't that they deserve less. The issue is actually that all of our kids deserve more," she said.
"Ultimately, we are about creating the next generation of leaders in this country. And they will come from all over the country. Therefore, we need to make sure all of them have access to the education that they deserve."