OSA Prescott Direct

Good M/A/E! Could you introduce yourself to the MOTJ?

Of course! Hi everyone, my name is Dr. Nat Prescott

Doctor, what do you do for a living?

I’m a senior engineer in the Fire research division of the National Institute of Standards and Technology.

What is the national institute of standards and technology?

It's a federal agency that does scientific research on engineering standards, fire safety, and disaster investigations. I examine electrical fires, how they start, and how they spread.

How’d you get into that line of work?

Well after getting my bachelors in Environmental Science from Colorado State University, I then became a firefighter. There I learned the importance of fire safety.

And that’s when I decided to go back to school to get my masters in electrical engineering from Emory University and my PhD in fire protection engineering from UC Berkeley.

Why are you in court today?

I was asked to evaluate the circumstances around the Dip Fire on January 1st, 2026, and analyze the potential causes.

I want to turn your work in today’s case.

Did you use a method?

I used a comparative analysis, which means I examined the evidence from the incident compared to the standards of care.

Did you have sufficient facts and data to come to a conclusion?

Yeah (chuckle) I reviewed the facts of the fire investigator’s report, MG&E’s monitoring records, and all the physical evidence from the police department. I also examined the scene.

Is your method reliable?

Of course, it's the gold standard in my field. I’ve used it reliably for all 28 times I’ve been retained as an expert, and it wasn’t any different with this one.

Does your opinion reflect a reliable application of a comparative analysis to the facts of the case?

Yes ma'am.

Let’s talk about your comparative analysis.

How’d you start?

To start, I looked at the fire report. It said that the fire started around dip road near rapid river valley. I then looked into what happened at that location that could have been the cause. And the report mentioned a car crash.

What did the car crash into?

There was a collision with a Toyota sedan and one of MG&E’s electric poles along dip road. When the police got to the scene, they didn’t report a fire, but still the police notified MG&E at 2:10 AM that the electric pole was leaning.

Well, if the police didn’t notice any fire, how did this all begin?

I actually brought along 2 models to help explain the case. May I?

What are we looking at?

In high school chemistry class, I'm sure you were taught about the fire triangle. The fire triangle explains how large fires start, keep going, and spread, including this specific fire. And all it needs are three things: heat, fuel, and oxygen.

Let’s start with the first of the three- what do you think was the heat?

There were a couple factors at play. When the car crashed into the pole, I determined that it left critical hairline fractures along the bushing in the transformer that was carrying the electricity.

Let’s break that down. How does the electricity get transmitted?

The whole electrical system is connected with wires. But that can get dangerous if the wires carry the same voltage generated at the power plants. So that’s why on an electric pole, there’s a metal box called a transformer.

Would you recognize a photo of MG&E’s transformer?

Yes

What is this?

This is (2b) a photo of the transformer on MG&E’s electrical pole that the car collided with.

Fair and accurate?

Yes

Doctor, are there wires inside a transformer?

Yes! A transformer, or this metal box here (2b), reduces the voltage of the electricity so it’s safe for the average household. You can’t see inside it, so that’s why I have this (demo). I know it looks a little silly, but my niece loves the sound of rain sticks. And I took one of them to explain how a wire works.

So how does this explain how electricity works?

Well this rain stick is a model of a wire. And these beads (hold up beads in tupperware) represent electricity. So if I pour these beads into the wire (pour), you can hear them flow through. (turn) Just like electricity flowing through the wires. But the difference is that electricity is hotter, with a greater electrical hazard. So unlike this cardboard, the wires are lined with insulation called bushing.

Doctor, you mentioned critical hairline fractures on the bushing. What happens if that’s the case?

Well when the bushing was compromised, it allowed this factor to escape the electrical lines (point). Heat.

What would that look like?

Remember a moment ago I talked about how electricity is like the beads? If you see here, if there’s damage, like a hole, (rip off tape), heat can escape. This is called electrical arching. Just like you need the rainstick to contain the beads, electricity needs to be contained by the bushing.

So does that immediately start a fire?

That’s a good question. It doesn’t. Think about it like this: just because one bead (hold one) flies out, doesn’t mean this is a spark and is going to reach the fuel on the ground, or even leave the transformer. But the longer it takes, and the more the electricity arcs (hold tupperware of all the beads), the more sparks there are. This is why it took about 1-2 hours for the fire to start.

Doctor, after the fire starts, what can keep it burning?

This leads us to our second factor: fuel.

Like gas?

That’s one type of fuel. In this case, the dry brush acted as a fuel for the heat, creating a path of dry grass and brush in the collision area.

Was there any dry brush?

Yes! When I went to look at the scene, there was dry brush only 2 to 4 feet from MG&E’s equipment. And because of the dry brush, it was able to travel to the transmission tower, and then to the homes.

So after the fire started, and after it was fueled, do you know how it spread?

Yes. third factor. Wind. I actually live near this area and had some friends over to celebrate new years. The wind was about 60 mph, it was so bad, they didn’t want to leave.

Now that we know how the fire may have been fueled, I wanna talk about what the defendant might have failed to do.

Are companies supposed to have regulations to prevent something like this?

Yes absolutely, there is a standards manual by UROC, or utility regulations and operations council. It’s the industry-wide reference used by MG&E and other Midlands utilities.

Doctor, based on your understanding of the UROC standards manual, how many of the safety policies did the defendant violate?

MG&E violated 3 standards

Let’s walk though each standard they violated. What did they violate first?

After a collision, a company should send out a trained field employee to examine the pole and see if there are defects.

Did the defendant check on the pole?

No

What about the second standard they violated?

If the Environmental Monitoring System on a pole detects the temperature and particulate levels rising together, it is likely not a mistake. This indicates a fire is growing and the company should de-energize the pole.

Did they de-energize the pole?

No