The same landfills and waste facilities have burned for years, while many causes remain unknown

In the early hours of 24 September, residents of Bakar, Čavle, Kostrena, Sveti Kuzam and Rijeka's Draga district received an alert telling them to close their windows and avoid being outdoors. Waste was burning across roughly 1,000 square metres at the Metis secondary-raw-materials facility in Kukuljanovo, and the national SRUUK warning system was activated because smoke was spreading towards populated areas.^[1]

At 6 a.m., the Martinšćica monitoring station recorded a PM10 concentration of 100.8 µg/m³. The Teaching Institute of Public Health of Primorje-Gorski Kotar County deployed mobile teams to the smoke-affected area and stated that the composition of the material involved in the fire was not yet fully known.^[2][3]

Only two days earlier, an entire hall at the Košer waste site near Pučišća on the island of Brač had burned down. Twenty-one firefighters and eight vehicles took part in the response.^[4] It was not the first fire there. On 30 July, firefighters had already fought a fire at the regulated Košer municipal-waste disposal site, with operations continuing through the night.^[5]

Two major incidents within two days attract attention. Looking further back reveals the more troubling feature: repetition.

The current fires are new, the pattern is not

Metis in Kukuljanovo also burned in August 2020, when a fire affected about 5,000 square metres of bulky waste and required 32 firefighters and 11 vehicles. The City of Rijeka also records another fire at the same site in January 2025, during which one firefighter was injured.^[7][6]

The repetition is not limited to a few nationally known facilities. At the Totovec landfill near Čakovec, processed and baled plastic burned in May 2019, prompting advice for residents of nearby settlements to close windows and remain indoors. About one hundred firefighters were involved.^[32] Totovec burned again in August 2024, this time in an area containing mixed municipal waste. After the fire was extinguished, the City of Čakovec said that spontaneous combustion appeared to be the most likely cause based on the information available at the time; 40 firefighters and 15 vehicles were involved.^[33]

An even longer sequence can be seen at Bikarac near Šibenik. Croatian Firefighting Association records show a fire at the regulated landfill in May 2019, a major landfill fire in July 2023 that spread to more than three hectares of vegetation and required aerial firefighting support, another mixed-municipal-waste fire in November that year, a landfill fire in October 2025 and another landfill fire in May 2026.^{[34][35][36][37][38]}

Drava International near Osijek suffered a major plastics fire in October 2023, another fire involving a large quantity of plastic in August 2024 and a PVC-packaging fire in September 2026.^[13][14][15] Košer on Brač burned twice in less than two months.^[5][4]

That does not mean those locations share a common cause. It shows something more limited but important: waste-management fires are not a sequence of incidents that always appear at entirely new sites.

Official annual figures add scale. The Croatian Firefighting Association, citing environmental-inspection data, records 11 landfill fires in 2019, 18 in 2020 and 19 in 2021.^[8] The State Inspectorate records 13 in 2022 and five in 2023, stating that the causes of all five were unknown.^[9] In 2024, ten landfill fires were recorded and the cause was again listed as unknown for all ten.^[10]

Those annual figures add up to 76 landfill fires from 2019 through 2024. Even that number is not perfectly clean: the 2024 report retrospectively says there were four fires in 2023, whereas the report dedicated to 2023 says there were five. A one-event discrepancy does not change the broader picture, but it shows that the official series itself is not fully consistent.^[9][10]

The category does not necessarily include every fire in a warehouse, sorting hall, recycling plant or other waste-management facility. The wider universe of waste-related fires reported in the news is therefore larger than the narrower official category of landfill fires.

An unknown cause is not evidence of arson

A long list of unresolved causes naturally fuels suspicion. The available evidence does not justify turning frequency alone into a conclusion that fires are being deliberately set.

Spontaneous combustion of waste is a real and well-described process. In large, heterogeneous waste masses, chemical and biological processes can generate heat, while oxygen, moisture and waste composition can affect self-heating and the potential for spontaneous ignition.^[11] Croatian official data support that mechanism: of 19 landfill fires recorded in 2021, 14 were attributed to spontaneous combustion within the landfill body and five to external influence.^[8]

Spontaneous ignition, however, does not automatically remove questions about the conditions that preceded a fire.

Drava International is the clearest example. In an indictment filed in 2024, the Osijek Municipal State Attorney's Office alleges that waste plastic was stored on an unprepared natural surface substantially larger than permitted, and that improper disposal, storage and mixing of hazardous and plastic waste led to chemical and physical processes and spontaneous ignition on 4 October 2023. The indictment also alleges inadequate fire-protection equipment and problems with fire routes, access for fire engines and hydrants.^[12]

These are allegations in an indictment, not a final court judgment. The case nevertheless illustrates why asking only whether a fire was deliberately set can miss the more relevant issue. A fire can start without a match or lighter while still raising serious questions about quantities of waste, storage practices and fire protection.

A similar issue emerged after the Eko-Flor fire in Zaprešić in June 2024. Across the response, 172 firefighters and 61 vehicles were deployed, with an estimated 14,000 square metres affected. A public warning was issued because of smoke, and firefighters detected an increased styrene concentration close to the fire.^[16] The Ombudswoman later reported that the State Inspectorate found that buildings involved in the fire were being used without an occupancy permit and contrary to their designated purpose, and that waste was not stored in accordance with the waste-management plan and permit.^[17]

Those findings do not by themselves establish the immediate cause of the fire. They show that after a major waste fire there are often two separate questions: how the ignition occurred and whether the site had been operating within the conditions allowed by law.

Deliberate fires have occurred, but a systematic model has not been demonstrated

There are cases where deliberate ignition was established.

After the 9 June 2018 fire at a C.I.O.S. Group facility in Zagreb's Jankomir district, police announced after the scene examination that the fire had been deliberately caused and that the criminal investigation was continuing.^[18]

In the public sources reviewed for this article, we did not find a later outcome that reliably establishes the perpetrator and motive. The case therefore demonstrates that arson at a waste-management site is not a fictional possibility. It does not demonstrate that operators systematically burn their own waste to reduce disposal costs.

The financial incentive to dispose of expensive waste illegally is, however, very real. In February 2025, Europol announced the arrest in Croatia of 13 people suspected of illegally disposing of at least 35,000 tonnes of medical and hazardous waste from Italy, Slovenia and Germany. Investigators estimated profits of at least EUR 4 million. According to Europol, the scheme depended on avoiding the costs of legally required treatment and disposal.^[19]

Croatia's Ombudswoman had already highlighted a related structural problem. Her 2023 report states that authorities sometimes identify violations and impose fines that companies pay while the underlying problem remains unresolved, warning against a business model in which breaking the rules and paying penalties is financially more attractive than lawful operation.^[20]

That is relevant evidence about the economics of waste crime. It is not evidence that fires are part of that business model.

Lack of transparency is documented, a cover-up is not

Waste fires are fertile ground for a leap from justified suspicion to claims the evidence cannot support. We found no solid evidence in the reviewed documents of a coordinated cover-up, destruction of evidence or falsification of air-quality results.

We did find documented failures in public communication and access to environmental information.

Following the July 2019 fire at Prudinec/Jakuševec in Zagreb, the Ombudswoman conducted an examination and concluded that residents had not been informed in a timely and complete manner about air quality and possible health hazards. Hazardous substances were identified in the burned waste, while the air analyses did not cover, among other things, benzo[a]pyrene in particulate matter, total gaseous mercury and several metals in total deposition. Dioxins and furans were not measured.^[21]

The Ombudswoman later stated that the State Inspectorate did not respond to her explicit request for soil analysis after the fire and did not provide data on soil sampling in 2020.^[22]

At Piškornica, the transparency issue received a formal decision. In 2017 the company rejected a citizen's request for an updated programme of measures concerning leachate management, arguing that the applicant was abusing the right of access to information. The Information Commissioner annulled the decision, finding that abuse had not been established and stressing both the environmental nature of the requested information and the public interest surrounding the Piškornica landfill.^[23]

None of that proves that evidence about fires was hidden. It does demonstrate that in some cases environmental information was incomplete, delayed or withheld until an oversight body intervened.

When waste burns, particulate matter is only part of the smoke

The Kukuljanovo fire provides a current example of the limits of rapid air-quality monitoring. The PM10 reading of 100.8 µg/m³ clearly showed a strong particulate pollution episode. At the same time, the county public-health institute stated that the composition of the burning material was not yet fully known and that additional targeted measurements could be carried out if necessary.^[2][3]

Depending on the material and combustion conditions, uncontrolled waste burning can emit particulate matter, carbon monoxide, volatile organic compounds, polycyclic aromatic hydrocarbons, dioxins, furans and other harmful substances. The World Health Organization identifies open waste burning as a source of air pollution associated with both acute and chronic health risks.^[24]

Croatia also has unusually concrete evidence for pollutants that a standard PM monitor cannot identify.

A Zagreb air study covering 1997 to 2000 found dioxin and furan concentrations between 9 and 306 fg I-TEQ/m³ in 28 ordinary samples. A separate sample collected during a landfill fire measured 13,200 fg I-TEQ/m³.^[25] That single event cannot be used to infer concentrations in Rijeka, Osijek or Brač today. It does show that a waste fire can create a chemical signal that cannot be reconstructed from PM2.5 or PM10 alone.

Another Croatian study examined a fire at the unsanitary Baštijunski Brig landfill. PCDD/F concentrations in sampled air increased by more than 4,000 times during the fire compared with the initial measurement, while elevated values were also recorded in landfill soil and nearby lake sediment.^[26]

A large landfill fire in Iqaluit, Canada, showed a similar mismatch. Health Canada researchers monitored PM2.5, ozone and NO2 alongside dioxins, furans, PAHs and volatile organic compounds. Median daily dioxin and furan concentrations during active burning were 66 times higher than after the fire was extinguished, while conventional criteria pollutants changed far less dramatically.^[27]

An AQI can therefore provide a useful warning that particulate pollution has increased, but it is not a chemical analysis of a smoke plume.

AirQuality.city currently calculates its overall AQI from PM2.5 and PM10, applying U.S. EPA AQI concentration breakpoints to the latest processed value available to the portal. This is not the official EPA NowCast or an official daily AQI. NO2, O3, SO2 and CO from official stations may be displayed separately but do not currently enter the portal's overall AQI. Even a more extensively equipped regulatory station does not automatically measure every compound that may matter in waste-fire smoke.

The difference between controlled thermal treatment and an uncontrolled waste fire, and the limits of a standard AQI around such facilities, are covered in more detail in our related article on waste incineration and air quality.

Osijek monitored the environment, but long-term health tracking ran into a system gap

After the Drava International fire, post-fire environmental assessment was substantially broader than after many earlier incidents. A scientific study published in 2025 examined agricultural soil within 20 kilometres of the fire, using samples collected three and 17 days after the incident as well as earlier control samples. For the analysed PAHs, dioxins, PFAS and heavy metals, the researchers did not find deterioration indicating a significant long-term threat to agricultural soil quality, and modelled cancer risks for the assessed exposure pathways remained within acceptable levels.^[30]

That is an important finding and a reason not to assume long-term contamination simply from the visual scale of a fire. It was not, however, an epidemiological study of people who breathed the smoke.

The Ombudswoman recommended that the City of Osijek and the county public-health institute conduct long-term health monitoring of residents and workers exposed during the fire.^[28] In the official report on implementation of those recommendations, the City of Osijek replied that it lacked a legal basis to monitor such health data, while the public-health institute stated that it did not know exactly who had been exposed and lacked the tools and authority to follow their medical records, examinations and diagnoses.^[29]

A recommendation for long-term health follow-up therefore existed, but there was no ready mechanism for carrying it out.

That matters particularly at sites where fires recur. A single short incident and repeated smoke exposure across several years are not the same public-health question.

A UK study published in August 2026 attempted to examine exactly that scenario. Researchers analysed healthcare data for 23,656 residents near the former Arnold's Field landfill in London and identified 99 fire days between 2018 and 2023. Among people with pre-existing chronic respiratory disease, GP attendance was 35% higher on fire days than on non-fire days. The study did not find statistically significant increases in general respiratory symptoms across the whole population, prescriptions, emergency-department attendance or hospital admissions.^[31]

The findings cannot simply be transferred to people living near Kukuljanovo, Osijek or Zagreb. They do show how much more can be learned when fire records, air measurements and health data are examined together over several years.

The smoke clears faster than the questions

There is enough evidence to see a pattern in Croatian waste fires, but not enough to turn every suspicious pattern into a conclusion.

The same landfills and waste facilities can burn repeatedly. In some years, spontaneous combustion has been the most frequently recorded cause. There is also at least one major case in which police established that a waste-facility fire was deliberately caused. After some major incidents, authorities have found serious irregularities in storage and fire protection, and the Ombudswoman has documented failures in timely and complete public information.^{[8][18][12][21]}

What remains unknown is just as important. The causes of all ten landfill fires recorded by the State Inspectorate in 2024 were listed as unknown. The same is true for all five fires listed in its 2023 report.^[9][10]

After every large waste fire, the public is left to reconstruct the same story from separate systems: a fire-service report, a police examination, an inspection, public-health measurements and, occasionally, later scientific studies.

When those data are published quickly and together, it becomes easier to distinguish measurable risk from speculation. When they remain incomplete or scattered, the smoke leaves room both for justified suspicion and for claims that the available evidence cannot support.

The fires on Brač and at Kukuljanovo will disappear from the daily news cycle. Their longer-term public value will depend on whether, months from now, there is a clear answer to four basic questions: what burned, why it burned, what entered the air, and whether anything was learned before smoke rises again from one of the locations we already know.

Chronological overview of confirmed fires

This is not an official register of every fire included in annual statistics, but a chronological overview of individual fires at landfills, storage sites and waste-management facilities that we were able to confirm through a specific publicly available source during this investigation. Where no final official cause could be found in the sources reviewed, that is stated explicitly.

• 14 Apr 2014 · C.I.O.S./CE-ZA-R, Jankomir, Zagreb
  Scale: Large open storage area; exact area not published. Material involved: Waste materials at a recycling facility, including plastic and metal. Cause: No final cause found in the public sources reviewed.^[39]

• 20 Aug 2015 · C.I.O.S., Jankomir, Zagreb
  Scale: Small fire; area not published. Material involved: Plastic. Cause: No final cause found in the public sources reviewed.^[40]

• 21 Aug 2016 · Piškornica, Koprivnički Ivanec
  Scale: Area not stated in the available overview. Material involved: Municipal waste at the landfill. Cause: No final publicly reported cause found.^[41]

• 3 Sep 2016 · Piškornica, Koprivnički Ivanec
  Scale: Area not stated in the official notice. Material involved: Non-hazardous municipal waste; reports also referred to burning plastic. Cause: The operator cited a chemical reaction deep in the waste; no final official finding was located.^[42]

• 1 May 2017 · C.I.O.S., Jankomir, Zagreb
  Scale: Major response involving 141 firefighters and 44 vehicles. Material involved: Wood and mixed waste, including wood, metal and tyres. Cause: No final cause found in the public sources reviewed.^[43]

• 9 Jun 2018 · C.I.O.S., Jankomir, Zagreb
  Scale: About 20 × 20 m. Material involved: Waste at the collection and processing facility. Cause: Police determined that the fire had been deliberately set.^[18]

• 2 May 2019 · Bikarac, Šibenik
  Scale: About 900 m². Material involved: Waste at a regulated municipal landfill. Cause: No final cause found in the public sources reviewed.^[34]

• 25 May 2019 · Totovec, Čakovec
  Scale: About 1.5 ha overall; roughly 2,700 t of baled plastic on a 50 × 20 m section. Material involved: Mixed municipal waste and baled plastic. Cause: Police investigation: spontaneous combustion of waste.^[44][45]

• 24 Jul 2019 · Prudinec/Jakuševec, Zagreb
  Scale: About 70 × 80 m, with waste 3 to 4 m deep. Material involved: Waste in the recycling yard. Cause: No final publicly reported cause found.^[46]

• 25 Sep 2019 · Tipos Resurs, former Mundus complex, Varaždin
  Scale: Production hall; area not published. Material involved: Facility used for recovery and temporary storage of waste plastic; the report did not specify the exact material burning. Cause: No final cause found in the public sources reviewed.^[47]

• 8 Aug 2020 · Metis, Kukuljanovo
  Scale: About 5,000 m². Material involved: Bulky waste. Cause: No final cause found in the public sources reviewed.^[7]

• 13 Aug 2020 · C.I.O.S., Jankomir, Zagreb
  Scale: About 100 m² according to one report. Material involved: Wood material during processing of wood waste. Cause: Ignition occurred during processing; no final police cause was located.^[48]

• 16 Jul 2023 · Bikarac, Šibenik
  Scale: Landfill plus about 3.15 ha of surrounding vegetation. Material involved: Waste at the landfill, grass and low vegetation. Cause: No final cause found in the public sources reviewed.^[35]

• 4 Oct 2023 · Drava International, Osijek
  Scale: Exact overall area not published; suppression and remediation continued for days. Material involved: A large quantity of plastic outdoors and part of a building. Cause: According to the indictment, improper storage and mixing led to spontaneous ignition; the case has not been finally adjudicated.^[13][12]

• 3 Nov 2023 · Bikarac, Šibenik
  Scale: About 2,500 m². Material involved: A large quantity of mixed municipal waste. Cause: No final cause found in the public sources reviewed.^[36]

• 19 Jun 2024 · Eko-Flor, Zaprešić
  Scale: About 14,000 m² of indoor and outdoor area. Material involved: A large quantity of plastic in storage. Cause: No final cause found in the public sources reviewed.^[16]

• 27 Jun 2024 · Jakuševec recycling yard, Zagreb
  Scale: About 2,000 m². Material involved: Waste in a fenced recycling area. Cause: No final cause found in the public sources reviewed.^[49]

• 7 Aug 2024 · Drava International, Osijek
  Scale: Exact area not published. Material involved: A large quantity of plastic outdoors. Cause: Short circuit: wind lifted aluminium foil into a power line and the resulting fire spread to waste below.^[14][50]

• 16 Aug 2024 · Totovec, Čakovec
  Scale: Area not published. Material involved: Mixed municipal waste. Cause: City of Čakovec: most likely spontaneous combustion.^[33]

• 12 Jan 2025 · Metis, Kukuljanovo
  Scale: Large pile of waste; area not published. Material involved: Waste on an outdoor storage area. Cause: No final cause found in the public sources reviewed.^[51]

• 2 May 2025 · Sodol, Ogulin
  Scale: Area not published. Material involved: Waste on the landfill body. Cause: Inspection record: caused by third parties.^[52]

• 12 Oct 2025 · Bikarac, Šibenik
  Scale: About 4,250 m². Material involved: Waste at the landfill and surrounding vegetation. Cause: No final cause found in the public sources reviewed.^[37]

• 12 Oct 2025 · Municipal-company warehouse, Čibača
  Scale: Hall and part of the storage area; area not published. Material involved: Paper and baled paper; spread to stored plastic was prevented. Cause: No final cause found in the public sources reviewed.^[53]

• 2 May 2026 · Bikarac, Šibenik
  Scale: About 1,000 m² of landfill and 2,500 m² of nearby vegetation. Material involved: Waste at the landfill, grass and low vegetation. Cause: No final cause found in the public sources reviewed.^[38]

• 30 Jul 2026 · Košer, Pučišća, Brač
  Scale: Area not published; firefighting continued overnight. Material involved: Municipal waste at a regulated landfill. Cause: No final cause found in the public sources reviewed.^[5]

• 31 Jul 2026 · Prapatnica near Prgomet
  Scale: About 2 ha including spread beyond the dump. Material involved: Bulky waste, then grass and low vegetation. Cause: No final cause found in the public sources reviewed.^[54]

• 1 Sep 2026 · Drava International, Osijek
  Scale: About 50 × 10 m. Material involved: PVC packaging. Cause: No final cause found in the public sources reviewed.^[15]

• 4 Sep 2026 · Sodol, Ogulin
  Scale: Area not published. Material involved: Waste at the landfill; reports referred to plastic. Cause: The cause was under scene examination and criminal investigation; city officials suspected arson, which had not been officially established.^[55]

• 22 Sep 2026 · Košer, Pučišća, Brač
  Scale: Entire hall/sorting facility burned; area not published. Material involved: Waste in the sorting facility, including a large quantity of plastic packaging according to reports. Cause: No final cause found in the public sources reviewed.^[4][56]

• 24 Sep 2026 · Metis, Kukuljanovo
  Scale: About 1,000 m². Material involved: Secondary raw materials, described by the company as bulky waste. Cause: The cause was still to be determined by the investigation and was not known at publication time.^[1]