The Hidden Threat on Every Dive

This last weekend, I was up in Alpena, Michigan, at the NOAA National Marine Sanctuary with my friend Stephanie Gandulla. We had invited Gareth Lock, from the Human Diver, to teach the 2-day Human Factors in Diving course. This was the second time I had him over, and the class was once again, powerful and poignant. 

Gareth has brought to the forefront of the diving community many new buzzwords like- Just Culture, Psychological Safety, and Non-Technical Skills, amongst others. But when reviewing the class materials afterwards, I was stuck on another one that really resonated differently for me this time. He calls it Performance Influencing Factors or Error Producing Conditions (EPCs).

When divers talk about safety, they usually talk about equipment or procedures. We’re told to “always check your gas,” “never hold your breath,” “always plan your dive and dive your plan.” These are good rules. But if you look closely at most accidents and near-misses in diving, the problem wasn’t the absence of a rule. The problem was that the rule wasn’t followed at the moment when it was most needed.

Why does that happen?
Well, you guessed it… Error Producing Conditions.

The problem with these EPCs, is that they are present on every single dive we make.

Error Producing Conditions are the subtle, often invisible factors that increase the likelihood of mistakes. They’re not usually dramatic. They’re ordinary. That’s why they’re so dangerous.

You stayed up too late the night before, and now you’re diving fatigued, or you woke up late and rushed out without any breakfast. You’re rushed, hungry, worried you may have forgotten something. 
Maybe you rented a regulator with a different hose routing than you are used to. You might be diving with a group of more experienced divers, and you don’t want to be the one to call the dive early. Or maybe the water is colder, darker, or murkier than you expected, and your stress level spikes.

None of these things automatically cause an accident. But each one chips away at your mental capacity, your attention, your judgment. Stack a few of them together, and suddenly the tiniest mistake can spiral into a cascade of problems.

That’s the essence of an Error Producing Condition. They make human error not just possible, but probable.
Most dive training focuses on what you should do in an emergency… clear your mask, check your gas, ascend slowly, share air if needed. These are mechanical actions. Gareth calls them, Technical Skills. Not to be confused with, “Technical Diving,” but rather the mechanical work of doing something underwater… and they’re important. But they exist inside a bubble where the diver is always calm, focused, and prepared.

And the reality is… reality is not like that.

Reality is messy. Divers are human. Humans are emotional, distracted, tired, overconfident, underconfident, stubborn, rushed, or sometimes just unlucky.

Ignoring EPCs means ignoring the truth of human performance. And that’s why, when accidents are analyzed, we so often hear the same story,
“He was a good diver…”
They knew better…”
I don’t understand why she did what she did…”

The answer isn’t that they didn’t know the rules. The answer is that these little Error Producing Conditions stacked up until the diver’s ability to follow the rules collapsed.

Not all EPCs come from inside our own heads. Some of the strongest come from outside of us. They come from the expectations of others.

If you’re on a charter boat, the clock is ticking. The captain wants the group in the water on schedule. The dive shop wants happy customers who get their full bottom time. Nobody wants to be the diver who surfaces early and “ruins the dive.” These pressures are subtle, but they are real. They whisper, “just a few more minutes… just a little deeper… don’t be the first one back on the boat.”

And just like any teenager who wanted to fit in with the cool kids at school knows, sometimes it’s peer pressure. Maybe you’re the only one in the group who wants to run through a detailed checklist, but everyone else is already zipping up suits and heading for the water. You feel the eyes staring at you. You feel the judgment. You tell yourself, “it’ll be fine… I can skip it… just this once.”

But every time you let those pressures override your training, you add an EPC into the system. You’re not just tired or rushed anymore, now you’re tired, rushed, and you are making decisions to please others instead of yourself. The error chain grows stronger.

The last few blogs I’ve written were heavily centered on DIR, Doing It Right. It is the cornerstone of the Mott Underwater Method, the mindset I try to build in my divers. Unlike most training systems, we don’t assume perfect conditions or perfect divers. We assume reality. A reality underwater where you’ll be tired sometimes. That you’ll feel pressure and that you’ll make mistakes.

This is where Gareth’s Human Factors compliments and enhances the Mott Underwater Method so well. Pre-dive and Post-dive, especially. 

The goal is not to eliminate EPCs, because you can’t. The goal is to train divers to recognize, manage, and adapt to them.

But how, you ask? 

1. Recognizing EPCs Early
Awareness is the first defense. Most divers don’t even realize when an EPC is present, because they’ve never been taught to look for them. Diver Preparedness and Situational Awareness are two of the founding pillars of DIR diving. 

This kind of awareness feels small, but it can change everything. Noticing that you’re rushing because the boat is about to leave gives you the opportunity to slow down deliberately. Catching the feeling of overconfidence before the dive starts can allow you to reset yourself and your situation. 

2. Training for Stress, Not Just Comfort
Most scuba training takes place in calm water, with a watchful instructor nearby, and plenty of time to think. That’s necessary at the beginning. But if training stops there, divers are left vulnerable.

In the Mott Underwater Method, skills are repeated under varied and sometimes stressful conditions, we call it Critical Skills Training within the UTD curriculum. 

It means taking a simple stationary skill and putting it into a real scenario that makes you think. Mask clearing when you’re calm is one thing, but mask clearing when someone turns around in front of you hurriedly and kicks your mask off… well, that’s where resilience is built. This is how you become a confident, thinking diver. 

By practicing with stress built into the training, divers create muscle memory and mental calmness that hold up even when EPCs are stacked against them.

3. Talking to Yourself (and Your Team)
This may sound strange, but it’s one of the most powerful tools I teach: self-talk.

When divers are stressed, their thoughts scatter. Their inner voice becomes negative or panicked. By learning to talk deliberately to yourself—“James, Check your gas. James, Breathe slowly. James, Focus and Stay calm.”—you anchor your mind and stop the spiral.

Equally important is normalizing communication with your team. Divers in stressful situations often go silent, afraid to look foolish or draw attention. But when constant, clear communication is the norm, small problems are caught early and addressed before they grow.

4. Designing for Consistency
The way you set up your gear, the way you plan your dive, the way you move through your pre-dive checks… it’s all important. Your mindset will either create EPCs or reduce them.

Diving Is Human
EPCs don’t just happen underwater. They happen in life.
If you take any Human Factors training from
Gareth Lock you will hear him say often that, “we are fallible creatures.” We get tired, we get stressed, we get distracted. Diving doesn’t erase that truth, it amplifies it.

Also,  if you’re a fan of my podcast, you’ll remember hearing Brando and myself saying over and over again that, “Diving is Life, and Life is Diving.” When you learn to manage EPCs underwater, you also learn to manage them on the surface. You learn awareness, resilience, communication, and consistency in a way that shapes you as a diver and as a human being.

That’s the real philosophy behind the Mott Underwater Method. It is why it is rooted in DIR diving and enhanced with Human Factors training with The Human Diver. Diving isn’t just about going deeper or staying longer. It’s about becoming the kind of person who can operate clearly and calmly even when conditions conspire against you.

Why now? 

The diving community is at a crossroads. We’ve spent decades focusing on equipment, procedures, and ACRONYMS. But the accidents keep happening. The near-misses keep piling up. And every year, more divers are surprised by how quickly “just another dive” can turn into something they weren’t prepared for.

The solution isn’t another gadget or another specialty card. The solution is learning how to be human underwater. That means understanding EPCs. That means building resilience against them. That means adopting a method that accounts for reality, not just theory.

You don’t have to wait until you’ve had a near-miss to start thinking about EPCs. You don’t have to wait until fear teaches you the hard way.

The Mott Underwater Method was built for divers who want more than just survival. It was built for divers who want to explore with confidence, who want to expand their limits safely, who want to become calmer, more deliberate, and more capable human beings both underwater and on the surface.

You can get started in this method with a regularly scheduled coaching program. We can dive into the water skills and thinking that make the DIR diver with the Essentials classroom from UTD Scuba Diving. Your brain needs training above water as well, and I’m hosting another Human Factors in Diving class with Gareth Lock again next year. Sign up and join us back in Alpena, MI at the NOAA National Marine Sanctuary. Or follow this link and get started right at home with the online Human Factors in Diving Essentials program. 

Because diving isn’t just about where you go. 
It’s about who you become in the process.