A report on the cargo, the fire, and the backfilling that followed at the accident site.
On 26 February 2023, a train entered Greece from the Gevgelija (Gevgeli) border station. Hellenic Train received of 18 open-type wagons loaded with steel sheets.
Two days later, at the Thessaloniki Freight Station, three of these wagons were placed behind the engine of the ill-fated freight train 63503, which departed for Athens. These wagons appear to be of significance.
The train collided laterally with the IC62 passenger train in Tempi, resulting in the deaths of 57 people. The fireball that formed and the subsequent blaze raised serious questions. Analyses conducted by the State General Laboratory detected samples of a flammable mixture of aromatic hydrocarbons at the crash site.
According to a technical report seen by NEWS247, which is now in the hands of the investigating judge, these flammable substances appear to have been placed together with steel plates in wagons 1, 2, and 3.
Position of the cargo on the train
According to the report by Achilleas Michopoulos, technical advisor to the families of the Tempi victims, the presence of flammable cargo in front of the steel plates caused the fireball phenomenon seen in the videos. The fireball lasted an unusually long time, likely due to successive releases and re-ignitions of combustible material.
Based on the findings of the State General Laboratory, the cargo that caused the fireball was a mixture of aromatic hydrocarbons containing high concentrations of benzol and toluene, as stated in the report.
The cargo, according to Michopoulos’ report, was distributed in three groups of 4-6 m³ (3 x 4-6 containers of 1 m³ each). The impact of the collision caused vibrations, which led to the dislodging of the sheet metals, dragging the tanks with them. The sparks generated ignited the flammable cargo.
Later, sheet metals from the three wagons were seen in photographs lying on the tracks, showing significant signs of thermal stress from the intense fire.
Findings included in the Anubis team’s report, now in the hands of the investigating judge, support the possible transportation of cargo on a wooden pallet secured with a strap. The presence of such items in any other wagon of the freight train, apart from the three in question, does not appear to be justified.
Firstly, because the other platforms of the freight train (wagons 4-13) remained intact, meaning their contents could not have ended up at the accident site. Secondly, because cargo in containers is secured using a different, significantly more modern method.
Findings by Anubis at the storage location in Koulouri, Larissa
Fireball and fire: two distinct phenomena
In December 2024, an analysis by the Piraeus Chemical Service confirmed that the fire that followed was not caused by silicone oils.
The report estimates that the freight train was carrying between 8.0 and 12.7 tonnes of polycyclic aromatic hydrocarbons. This estimation is scientifically supported by a Cascade Release model analysis for the fireball, along with a series of other measurements and tests conducted in scientific research programmes.
The phenomenon observed in the videos represents the first phase, known as the fireball. Based on calculations, between 3.8 and 5.4 tonnes of material were burned in this stage. However, according to the report, the fireball itself does not appear to have contributed to the fatalities.
The leakage of chemicals from the transport containers played a more significant role than the visible fireball seen in the videos. The amount of aromatic hydrocarbons spilled onto the ground is estimated to be between 8.9 and 12.6 tonnes. This led to a second-phase fire, known as a pool fire, which did not develop in the atmosphere but at ground level—where passengers were located.
According to the report, the ground fire ignited approximately 01:22” after the collision. It was most likely triggered by the contact of the hydrocarbon vapour cloud with a surface that had overheated due to friction, acting as a hot ignition source, similar to a spark.
Scientific literature indicates that once ignited, the vapour cloud initially causes an explosion (detonation), leading to a rapid expansion of the fireball. The combustion then transitions into slower burning (deflagration). This phenomenon is internationally described by the term DDT (Detonation-Deflagration-Transition).
Charred bodies were recovered from the wreckage of wagons B1 (canteen) and B2. The report argues that, since some passengers from the canteen car survived without burn injuries caused by radiation, it is impossible that any body was charred due to the fireball alone.
Therefore, the report concludes that victims who survived the initial collision lost their lives not because of the fireball but due to the burning mixture of aromatic hydrocarbons that continued to burn on the ground (deflagration) after the crash.
What happened with the backfilling
The aromatic substances that did not burn were absorbed into the soil. Sampling conducted by the State General Laboratory at the accident site one month later detected unknown quantities of various flammable aromatic and polycyclic aromatic hydrocarbons.
Their presence in the ground made work at the site nearly impossible—firstly, because the atmosphere was suffocating, and secondly, because there was a risk of re-ignition.
Whoever decided on the immediate remediation of the area by removing the contaminated soil from the crash site likely acted correctly from a safety standpoint.
However, it is clear that—even at that moment—they must have already known that the soil did not contain silicone oils but highly flammable and hazardous materials.
Summary
The report confirms that the freight train was carrying hazardous flammable cargo, including polycyclic aromatic hydrocarbons (benzol, toluene), stored in open wagons 1, 2, and 3 alongside sheet metals.
The fireball seen in videos resulted from the ignition of hydrocarbon vapours due to the collision, but it was not the primary cause of fatalities. Instead, the pool fire at ground level, caused by spilled hydrocarbons, was responsible for most deaths.
The cargo was likely transported on wooden pallets with straps, rather than in modern secure containers. The collision dislodged sheet metals, dragging the tanks and creating sparks that ignited the fire. The burning process followed a detonation-deflagration-transition (DDT) pattern, meaning an initial explosion followed by sustained burning.
Environmental testing found unburned hydrocarbons in the soil, making the site dangerous due to toxic fumes and re-ignition risks. Authorities quickly removed contaminated soil, suggesting they were aware of the hazardous materials early on.
Ultimately, the report highlights serious safety concerns, raising questions about cargo handling, transport regulations, and accountability in the Tempi train disaster.
Also read: I HAVE NO OXYGEN: Thousands demand justice for the Tempi victims worldwide
Photos source: news247
With information from: news247-Alexandros Litsardakis and Achilleas Michopoulos technical report
