Did Serbia use “poison gas” on students? Short answer: Tear gas, yes. CN “poison gas,” unproven.

Students say police fired an older, more toxic agent—CN—during a chaotic night in Novi Sad. Police flatly deny it. We chased the lab report that could settle it. It hasn’t been published.

The night of Sept 5: What’s confirmed, what’s contested

• What’s confirmed:

  • Police did use tear gas and stun grenades to disperse large anti‑government protests at the University of Novi Sad on Sept 5, 2025. Multiple outlets reported clashes that night. Reuters
  • Protesters and some police experienced severe effects, including vomiting, according to N1’s English‑language reporting. This speaks to intensity of exposure, not the specific chemical. N1

• What’s contested:

  • Students at the Faculty of Science and Mathematics (PMF) say they collected spent canisters and that “independent analysis” detected both CS and CN. However, no named laboratory or full report has been made public in the sources we reviewed. Danas
  • The Interior Ministry (MUP) “categorically denies” any CN use, saying police do not possess CN agents and used only CS‑based munitions (MN‑01 rounds, RB‑N2 hand grenades). RTS

Bottom line: CN use remains unproven. There is a sharp dispute between student accounts and the Interior Ministry’s denial—and no publicly verifiable lab documentation yet.

Why CN vs CS matters (and what “banned” really means)

• CN (chloroacetophenone) was synthesized in Germany in 1871 and used historically as a tear agent; it’s more toxic than modern CS and has largely been phased out. Wikipedia
• Both CN and CS are “riot control agents.” Under the Chemical Weapons Convention, using them as a method of warfare is prohibited. Domestic law‑enforcement use is not per se banned. OPCW
• CN has wartime history: U.S. documents indicate CN was authorized in some Vietnam War situations alongside CS. US State Dept. historical docs

So calling CN “internationally outlawed” is partly right—if you mean in war. That does not automatically make domestic police use illegal under international law (national laws vary).

The politics: Sharp words from the top, and a geopolitical backdrop

• President Aleksandar Vučić has labeled protesters “terrorists” and suggested Western backing—without providing evidence. Multiple outlets reported this rhetoric. AP
• He met Vladimir Putin twice in 2025 (Moscow in May; Beijing in early September), and also met Xi Jinping in Beijing around China’s WWII commemorations. Vreme PRC MFA
• Serbia remains an EU candidate; Vučić publicly supports joining, even as ties with Moscow and Beijing deepen. European Commission

What we verified, what we didn’t—and why that matters

Our reporting steps:

1. Cross‑checked protest accounts with wire services: confirmed tear gas and clashes. Reuters
2. Searched for a named lab or a published analysis supporting the CN finding: none located in materials from PMF students or outlets quoting them. Danas
3. Reviewed the Interior Ministry’s detailed denial and claimed inventory (CS‑only munitions): confirmed their categorical stance. RTS
4. Checked medical‑effect reports: found descriptions of vomiting but no hospital‑level toxicology tying symptoms to CN specifically. N1

What would settle the dispute:

• A publicly released, peer‑reviewable lab report naming the laboratory, methods (e.g., GC‑MS), chain‑of‑custody for recovered canisters, and quantifiable findings for CN/CS residues.
• Serial numbers or procurement records for munitions used that night, independently verified.

Important corrections and nuance to the original article

• Bold claims about CN:
  • The piece states CN is “internationally outlawed.” Correction: Using any tear agent in war is banned; domestic police use is not per se prohibited under the CWC. OPCW
• Source attribution error:
  • The article cites a portal “EU alive.” We found no such news outlet covering these events. Serbian media that did report the student allegations include RTS, N1/Beta, Danas, and Vreme. RTS Danas
• Media freedom claim:
  • “Hardly any independent media left” overstates a grim situation. Serbia ranks 96/180 in RSF’s 2025 index; independent outlets like N1, Danas, Vreme, and 021.rs still operate—under sustained pressure. NIN/RSF summary
• August TV‑show remark:
  • We did not verify a specific quote in which Vučić scolded police for not being “harsh enough” in Novi Sad on TV. We did find August statements promising a tough response and denouncing protesters as violent. Verdict: unverified as phrased. Washington Post

Key takeaways

• Tear gas was used in Novi Sad on Sept 5. That is verified.
• The claim that police used CN, an older and more toxic agent, is an allegation without a publicly verifiable lab report. The Interior Ministry categorically denies it.
• Calling CN “internationally outlawed” needs context: banned in warfare, not categorically banned for domestic policing.
• Vučić’s rhetoric toward protesters (“terrorists”) is documented; his meetings with Putin and Xi this year are confirmed; Serbia’s EU path remains official policy.

What to watch next

• Will students publish a named lab analysis with full methods and chain‑of‑custody?
• Will an independent body—ombudsman, forensic institute, or international organization—test recovered canisters?
• Will the MUP disclose procurement records for MN‑01 and RB‑N2 used that night, or allow independent inspection?

Until then, the “poison gas” question has a sober answer: tear gas, yes; CN specifically, unproven. The truth likely sits inside a canister—and a lab report the public can read.