Early in the afternoon of December 11, 2012, a high-pressure natural-gas pipeline ruptured in Sissonville, West Virginia, 14 miles north of Charleston. The gas ignited, and the flames incinerated three homes and melted an 800-foot section of Interstate 77. Witnesses turned to similes to describe the fire. To one, the roaring “sounded like a turbine engine.” To another, “it was like a space flight.” Governor Earl Ray Tomblin toured the site after the fire was out. “It was like walking on a volcano,” he said. Incredibly, nobody died. “We were very lucky—no rush-hour traffic,” said a volunteer fireman.

Such luck doesn’t always hold. In Malta in 2013, a lifeboat fell from the side of the cruise ship Thomson Majesty during a drill, killing five people. In Guadalajara in 1992, a series of sewer explosions killed 252. In 1971, British European Airways Flight 706 crashed en route from London, and all 63 people on board died. What, you might ask, do these incidents have to do with the Sissonville fire? They, and thousands more, share a direct and seemingly mundane cause: corrosion. Crucial equipment rotted and failed. They also share a proximate cause: invisibility. The signs of danger were easy to ignore.

In thrall to the era of Little Digital, we overlook that this is still the era of Big Analog. Our mobile, personal, wireless world is utterly reliant on a massive, interwoven, mechanical counterpart. And lots of that big stuff is rusting. Every four years, the American Society of Civil Engineers releases its Report Card for America’s Infrastructure. The latest, from 2013, gives the country a D+ overall. Broken down by category, our ports get a C; energy gets a D+; aviation, dams, drinking water, hazardous waste, roads, transit, and wastewater all get D’s; inland waterways and levees, each a D–. Rail manages a C+, as do bridges. Solid waste leads the class with a B–. Shortfalls in investment and innovation play a role in our poor showing. But the main problem is simple deterioration. Public and private dollars have been poured into building American infrastructure. They have been in limited supply for the task of maintaining it. I’m tempted to invoke a cliché and say that the deterioration is happening before our very eyes, but that would miss the key point: the deterioration is happening, and we’re not seeing it at all.

The hidden world of corrosion is the subject of the journalist Jonathan Waldman’s lively book, Rust. Don’t be put off by the subtitle, The Longest War. Waldman has embarked on the opposite of a slog. Among several diversions, he takes his readers along on a break‑in at the abandoned Bethlehem Steel Works with a fine-art photographer. We also get to witness a low-stakes but high-tension infiltration of the Can School, an annual confab on food-preservation technology hosted by the Ball Corporation, of jam-jar fame. (Its attendees, Waldman discovers, would prefer not to talk about the controversial synthetic compound BPA in their can-lining polymer coatings.)

Waldman’s central concerns, however, and the subjects of his two most compelling chapters, are the rusting of America’s military and industrial equipment and the reasons we’re so bad at combatting it. The characters who anchor his narrative could not be more different. Daniel J. Dunmire, now in his 60s, has a history of quirkiness. For years he drove a car painted like a Pittsburgh Steelers helmet. A committed Trekkie, he scripts educational anticorrosion videos narrated by his now-pal LeVar Burton (known to fans as Lieutenant Commander Geordi La Forge of the starship Enterprise). Dunmire is the director of the Pentagon’s Corrosion Policy and Oversight Office, the first person to hold that position. In the Defense Department’s hierarchy, he is two steps below the secretary.

The latest Report Card for America’s Infrastructure gives the country a D+.

Bhaskar Neogi was born in 1971 in Kolkata and moved as a boy to Bangladesh, then to Kenya, then to Uganda, Dubai, Tanzania, and Ethiopia. In 1989, he moved to the United States. He speaks five languages and has an engineering degree from the University of Alaska. At home, watching tropical fish in his custom-built 2,400-gallon saltwater aquarium relaxes him during the rare hours when he is not worrying about the state of the Trans-Alaska oil pipeline, whose structural integrity is his professional and personal passion: he’s been the senior director of risk and compliance for the Alyeska Pipeline Service since 2013. When he’s on the road, he calms himself by humming Beethoven.

Yet the two men share a common approach to keeping corrosion at bay. Both contend not just with the technical but also with the cultural challenges of the problem. One of Neogi’s most important tasks is “pigging the pipe”—sending a submarine-like sonogram machine down the entire 800-mile pipeline to identify rusted-out spots that need repairs. Under Neogi, improving the pig’s abilities has been a priority; the latest model, 16 feet long and weighing five tons, cost $2 million and was a bargain at that price. One leak, according to Neogi, and “the company’s looking at over $1 billion in problems: image, cleanup costs, respect in Alaska.”

Dunmire’s technical solutions are less gee-whiz. Millions of dollars have gone toward developing better paint. Other line items include dehumidifiers and covers to protect aircraft being sent overseas by ship. It appears to be simple, even droll, work—but the Government Accountability Office calculates that Dunmire’s programs average a return-on-investment ratio of 14 to 1. In less than a decade his initiatives, by Waldman’s calculations, have saved the Pentagon billions of dollars.

Both men’s successes reflect a change in the culture of their employers. Under Neogi’s predecessor, according to Waldman, Alyeska failed in three successive attempts to pig the pipe—three chances to diagnose and prescribe fixes for a disaster waiting to happen. Neogi produced a nearly comprehensive scan of the pipeline—the most complete in years, comprising 400 gigabytes of data—on his first try. “I want to know exactly what’s going on,” he said, summing up the ethos of vigilance he embodies at Alyeska.

Dunmire was a bold pioneer in delivering a plainspoken diagnosis of the Pentagon’s rust problem: “Manufacturers want stuff to break. They design stuff to break.” His prescription was equally blunt: “We’re a capitalist society. We cannot afford for the DOD to be a profit center in the business of corrosion. We have to break this cycle.” That business costs the Department of Defense $15 billion to $20 billion a year. Today, thanks to his often lonely crusade, every Defense weapons proposal must plan for corrosion prevention and control. Tony Stampone, a colleague at the department, says, “No one had heard of corrosion before. No one cared. Dan got the word on the radar. If you can do that in the Pentagon, that’s half the battle.”

Technological advances and cultural change can do only so much to fight rust, however. We can greatly slow corrosion, but we cannot stop it outright. Exposed iron and steel naturally revert to their lowest energy states by giving up their electrons to oxygen and water. The process is formally known as oxidation. Informally, it’s called rusting. By any name, it’s inevitable. “We’re fighting the second law of thermodynamics,” Dunmire likes to say.

At some point, higher concerns must come to bear in a war we can’t win but can’t afford not to wage. Changing America’s report card from a D+ to a B, according to the American Society of Civil Engineers, would take $3.6 trillion of investment by 2020. The current shortfall, by the organization’s estimate, is $201 billion annually. The odds of closing that gap, and the costs of failing to, are similar to the odds and costs of the next bridge you drive across collapsing while you’re on it: respectively, minuscule and catastrophic.

Waldman, who has tracked down good sources in the little-known realm of corrosion experts, quotes one of them blaming America’s wealth for our failure to address the problem of infrastructure rot: “The more money you have,” Mike Baach observes, “the more reckless you are.” We do appear stuck in the bullish mind-set of the mid‑20th century, behaving as though we are rich enough to buy all the new bridges we want and too rich to worry about fixing all the old bridges we have. “We can’t afford it anymore,” Baach argues. “Is it a moral issue when a busload of kids will get killed when a bridge falls? You can’t separate them. It’s moral and it’s economic.” More than a few critics have lately been encouraging the United States to get its house in order. The country could do worse than to take the advice literally.