The Lineage cold-storage warehouse in Boyle Heights burned for roughly a week, according to news reports, from June 17 through its June 24, 2026 knockdown. By the time crews declared it contained, the cause was already disputed between the parties and, per LAFD, still undetermined; Governor Newsom declared a state of emergency on June 20. For the attorneys who will spend the next two years litigating who pays for that loss, the fight will not turn on how dramatic the footage looked. It will turn on whoever puts the more defensible fire investigation expert witness on the stand.
In large-loss fire litigation, the building is gone. The inventory is gone. Much of the physical evidence has been hosed down, bulldozed, or burned past recognition. What remains is a reconstruction, and a reconstruction is only as good as the person who builds it and the methodology behind it. When the cause is genuinely contested, the case stops being about the fire and starts being about the witness.
Why a Disputed Cause Changes the Entire Case
When everyone agrees a fire started in a particular electrical panel, the dispute is usually about duty, maintenance, or damages. When the cause itself is open, as it reportedly remains in Boyle Heights, where investigators have not announced a determined cause and the parties disagree about how it started, the origin-and-cause analysis carries the whole matter. Subrogation, product liability, premises liability, and any criminal exposure all branch off the same root question: where did this start, and what set it off?
A cold-storage facility complicates that question in specific ways. These buildings combine industrial refrigeration systems, large electrical loads, ammonia or other refrigerants, thick layers of insulation, and racking that can collapse early and bury the area of origin. A fire that burns for the better part of a week consumes the very evidence an investigator needs, and the long, hot exposure can make a secondary burn pattern look like a point of origin. An expert who does not understand how that environment behaves will reach a tidy conclusion that an opposing expert can take apart.
So the first job for counsel is not finding someone who will say what you want. It is finding someone whose reconstruction will still stand after the other side has spent months trying to knock it down.
How a Fire Origin and Cause Expert Rebuilds the Ignition Sequence
A credible fire origin and cause expert works backward from the damage to a sequence, not forward from a hunch to a conclusion. The recognized framework is the systematic approach in NFPA 921, the guide to fire and explosion investigations, paired with the scientific method: define the problem, collect data, form a hypothesis, test it against the evidence, and discard hypotheses that do not hold.
In practice the expert reads the building. Burn patterns, depth of char, the direction of heat and smoke movement, the failure sequence of materials, witness accounts, alarm and suppression records, utility data, and fire-modeling software all feed a single question: what story explains every piece of physical evidence, not just the convenient pieces?
The discipline that separates a strong expert from a vulnerable one is the willingness to say "undetermined." NFPA 921 expects an investigator to rule out alternative causes before settling on one, and an expert who jumps to "electrical fault" or "arson" without excluding the competing hypotheses has handed the cross-examiner a roadmap. In a fire that burned as long as this one, the honest answer to certain sub-questions may be that the evidence no longer supports a confident finding. Treat an expert's candor about the limits of the data as a feature. A witness who admits what they cannot know is far harder to impeach on the things they do.
Surviving a Sargon Challenge in California Court
In California, expert opinion is gatekept under Sargon Enterprises, Inc. v. University of Southern California and Evidence Code sections 801 and 802. The trial court confirms that the opinion rests on matter a reasonable expert would rely on and on reasoned methodology, and excludes testimony built on speculation or an analytical gap between the data and the conclusion. That gap is the phrase courts return to: it is not enough to be qualified and to have looked at evidence. The reasoning has to connect.
For a fire investigation expert witness, that gatekeeping maps almost perfectly onto NFPA 921. An expert who can show, step by step, how the physical evidence was collected, which hypotheses were tested, and why the rejected ones were rejected has a methodology a court can see and trust. An expert who reverse-engineered a conclusion to fit the client has a result the court can exclude before the jury ever hears it.
So the time to stress-test your expert is at retention, not at the motion hearing. Ask how they document hypothesis testing. Ask how they handle a scene where the area of origin was destroyed. Ask what would have to be true for them to revise their opinion. The expert with clean answers to those questions is the one who survives a Sargon motion. The expert who treats the questions as an insult is the one you do not want to learn about under oath.
What This Means for the Litigation Ahead
Cases like the Boyle Heights fire tend to consolidate, and the early origin-and-cause work shapes everything that follows. The party that engages a methodical investigator quickly, while the scene and the documentation are still fresh, controls the narrative the other experts have to answer. The party that waits inherits whatever the evidence has become.
Retain the origin-and-cause expert early, vet for documented NFPA 921 methodology rather than for the conclusion you hope to hear, reward candor where the data demands it, and match the expert to the building, because cold-storage, industrial refrigeration, and ammonia systems are their own specialty. The practical step is to start vetting before you need the opinion in a brief. If you are building a short list of qualified investigators, you can browse fire expert witness Los Angeles listings in the directory and compare credentials, prior testimony, and specialties in one place, rather than working the phones cold while the clock runs on a disappearing scene.
This article is general information for attorneys evaluating expert witnesses and is not legal advice.