Ship a care package of baked goods to your buddy across the country, and you probably don’t expect that they’re going to ride along next to a heap of plutonium. But here we are.

A bombshell report from the Center for Public Integrity this week revealed that Los Alamos National Laboratory “improperly shipped unstable, radioactive plutonium in three containers to two other government-owned labs via FedEx cargo planes.”

In other words, nuclear bomb materials rode through the air alongside folks’ Ebay purchases and overnight cookie shipments.

So what does that mean?

The CPI identifies a number of risks, real and theoretical, that emerged from sending actual friggin plutonium via a company best known for not being UPS and for eating Kinkos — the most significant occurring when a container of the stuff was opened in a university lab without proper safety precautions.

Inverse was curious though: How dangerous was it for the FedEx employees unwittingly tasked with carrying radioactive material around? What about the folks whose packages shipped alongside it? Are the cookies in that care package going to mess you up inside?

Getty Images / Sean Gallup

How Radiation Messes You Up

If you want to understand the risks of radiation, you have to understand what it is and why it’s dangerous.

Radioactive materials for the most part are materials made up of atoms so big and heavy that they fall apart over time. Protons and neutrons pop off individually or in big chunks, and ricochet out into space. With each pop, a small flash of energy is created, the electromagnetic equivalent of the crack of an apple falling from a tree.

The most famous example of this is a nuclear explosion, when billions of atoms split all at once in a deadly flash. But mostly the process is much slower, taking place invisibly over anywhere from a few decades to millions of years.

With each POP and zing of an atom decaying into its constituent parts, every living thing in the area ends up in a bit more danger. Those particles can slip through the gaps in clothing, skin, and the molecules of skin only to crash at high speed into individual strands of DNA, knocking them into all-new shapes. And the electromagnetic rays emitted can do something similar, interacting with a living thing’s biological code and permanently altering it. Imagine a car, pitted and scraped up after sitting under a tree that decided to drop all its apples. That’s your DNA after prolonged exposure to radiation.

In small doses, this is a problem because it drives up the risk of cancer — the risk that an error in a cell’s code will cause it to lose control, overwhelm its host body years or decades later, and potentially kill it.

In high doses, it’s a problem because cells start to die outright throughout the body. This is called radiation poisoning.

Some radiation is fine, but for God’s sake be careful

One bit of good news is the body is really good at correcting genetic errors that result from radiation poisoning. Otherwise the background radiation folks encounter from taking a plane flight, getting a tan, sleeping with their partners, or eating bananas would be sure to kill them.

That said, regular exposure to radiation is a real problem. And that’s why institutions charges with handling radioactive material (like Los Alamos) are supposed abide by strict procedures in handling them.

Another bit of good news is that those procedures are so robust, they can probably stand up to foolhardy errors like the decision to use commercial cargo jets for shipping.

Containers like the ones that seem to have been used in these cases are specially designed to block all the major forms of radiation plutonium can release. Big chunks of neutrons and protons falling that fall off of atoms can pass through skin, but they can’t pass through just anything. Even a few feet of soil or water can significantly reduce the danger to people nearby. The lead and compressed argon that get used, carefully welded and compressed, to build plutonium canisters, are even more effective shields.

All, or nearly all, of the particles and rays would have collided with the solid, dense particles of the container packed in around them. Imagine that rain of apples falling out of a tree, but getting caught in thick brambles and netting on the way down. Any FedEx workers nearby were almost certainly none the worse for the wear after the shipment, and not a single cookie in that care package would have tripped a geiger counter.

Los Alamos National Lab Flickr / Larry1732

How things could have gone very poorly

While these FedEx shipments almost certainly went down without incident (at least for any FedEx employees), there’s still a very good reason why Los Alamos is in hot water for making it happen.

Like any piece of technology, plutonium containers have their stress limits and failure conditions. The biggest ones are high impact and heat.

If the FedEx plane had caught fire on the tarmac or crashed for any reason — a rare enough thing, but not unheard-of — the heat of burning jet fuel might have eventually caused the canister to split open. Once that happened, the billowing air around the flames would have aerosolized particles of plutonium and spread them around the surrounding area. This is pretty much a worst-case scenario for nuclear material transportation.

Even worse, it’s unlikely that anyone would have immediately realized that there was a radiation hazard underway, because Los Alamos hadn’t told anyone there was nuclear material in the package. Rescue personnel, crash survivors, and anyone living or working nearby would have been at an incredible risk.

So, hey, nuclear scientists: Can we stick to the rules next time?