Red Line Edge: Why Europe Fears Russia's Escalation of Chemical Weapons Threat on the Ukrainian Battlefield

In the Donetsk region of eastern Ukraine, within a trench repeatedly scarred by artillery fire, several Ukrainian soldiers experienced severe coughing, vomiting, and blurred vision on a certain morning in late 2023. They had not encountered conventional shelling; instead, they reported a pungent odor resembling a mix of chili peppers and rotten apples drifting across their position. Subsequent records from the Ukrainian military command classified this incident as a K-51 chemical munition attack—just one of over 9,000 documented cases of Russian forces using chemical substances since February 2022. However, in strategic analysis rooms in Brussels, London, and Berlin, a deeper concern is spreading: could these tactical violations involving tear gas and choking agents be merely a prelude to a more lethal threat?

A recent series of reports by The Times of the UK, combined with assessments from intelligence agencies across multiple European countries, reveals a scenario that keeps Western defense circles awake at night: a stalemated or indefinitely prolonged war in Ukraine could ultimately force the Kremlin to cross a darker threshold—the use of weapons of mass destruction, specifically chemical weapons. This concern is not unfounded; it is rooted in Russia's past behavioral patterns, its undisclosed military capabilities, and the increasingly brutal reality of attrition on the current battlefield.

From Tear Gas to "Novichok": A Faintly Discernible Escalation Path

Data provided by the Ukrainian military outlines a systematic use of chemical substances on the battlefield. Out of over 9,000 recorded instances, 6,540 occurred just last year. Most of these incidents involved grenades or drone-dropped devices filled with riot control agents such as CS and CN. While not intended to cause immediate fatalities, these substances effectively weaken the combat effectiveness of defending forces, compelling soldiers to remove their protective gear and thereby exposing them to subsequent firepower.

However, what truly struck a nerve in Europe was the ghostly resurgence of older, more lethal chemical agents. Ukrainian and European officials have accused Russian military forces of occasionally using chloropicrin. The reappearance of this substance, which caused agonizing suffocation among soldiers in the trenches during World War I, signifies a loosening of certain taboos. Dutch and German intelligence agencies assessed in 2023 that the use of chloropicrin in Ukraine had shifted from sporadic incidents to a regular phenomenon. Ukrainian authorities claim that at least 3 soldiers have died from exposure to chemical agents.

Analysis indicates that the use of these low-end chemical weapons itself constitutes a blatant trampling of international law, violating the 1993 Chemical Weapons Convention and the 1925 Geneva Protocol. The European Union has already imposed sanctions on three Russian military units suspected of developing and using chemical weapons based on this in May 2023. However, Western anxiety lies in the fact that these observed substances may only be the tip of the iceberg of Russia's chemical arsenal.

The core of the issue lies in Russia's never truly terminated chemical weapons program. In 2017, Russia publicly announced that it had completely destroyed its chemical weapons stockpile, fulfilling its international obligations. However, the Novichok nerve agent attack in Salisbury, UK, in 2018, along with the similar poisoning of opposition figure Alexei Navalny in 2020, completely exposed this claim. Investigations by Bellingcat concluded that Russia's Novichok development program lasted far longer than the official termination date announced by the Kremlin.

More disturbingly, it is the pattern of continuation that stands out. Bellingcat's investigation indicates that scientists involved in the development of nerve agents were transferred to so-called civilian institutions, such as the State Research Institute of Military Medicine and the Signal Science Center, allowing weaponization research to continue under the guise of medical and industrial projects. Former British Army officer Hamish de Bretton-Gordon was unequivocal about this: it can be safely assumed that Russia's chemical weapons program remains active... If 'Novichok' were to be used on a larger scale, the consequences could be enormous.

Deadlock and Despair: The Strategic Breeding Ground for Extreme Options

Why is Europe so concerned about escalation now? The answer is closely linked to the current state of the war. Entering its third year, the frontline has become highly deadlocked after Ukraine's 2023 counteroffensive failed to achieve a decisive breakthrough. Despite paying a heavy price, Russian forces have recently made slow but steady progress in certain areas, though far from reaching their strategic objectives. The ceasefire conditions proposed by Kremlin spokesperson Peskov—the complete withdrawal of Ukrainian troops from the Donbas region—are deemed unacceptable by Kyiv, leaving peace talks at a dead end.

In this war of attrition, time becomes a cruel weapon for both sides. For Russia, although its war machine has shifted to a wartime footing, continuous personnel casualties, equipment losses, and the long-term effects of Western sanctions are constantly eroding its national strength. When conventional military means cannot quickly break the deadlock, and political and economic costs continue to rise, the temptation for decision-makers to seek asymmetric or breakthrough measures increases.

The analysis by General Richard Barrons, former commander of the UK Joint Forces Command, captures the logic of this dilemma. He believes that shifting toward more lethal chemical weapons would be a bad move for Moscow, as the military gains are limited while the costs are significant. "You would draw attention to a war crime, you risk retaliation, and it’s a double-edged sword—you could endanger your own troops, for example, if the wind changes direction," Barrons pointed out.

However, the warning that followed is the essence of Europe's concern: But if you find yourself in a situation where the stakes are extremely high and the survival of the nation is at stake, the temptation to use such weapons may arise. This is precisely the most terrifying trigger for a deadlock in strategic analysis. If the Kremlin leadership feels that the survival of its regime is fundamentally threatened, or believes that losing the war would lead to its domestic political collapse, all calculations regarding international reactions and moral costs may be cast aside. The use of weapons of mass destruction, such as chemical weapons, could be seen as a last resort to reverse the battlefield situation, create panic, and force Ukraine and its allies to submit.

It is worth noting that while Putin frequently brandishes the nuclear deterrence card in public, he remains almost silent on chemical or biological weapons. This silence itself may be a deliberate strategy of ambiguity. Former MI6 chief Alex Younger pointed out that the West is closely monitoring the Kremlin's actions. This ambiguity serves both as a deterrent and reserves room for future escalation, making it difficult for opponents to predict and guard against.

The Western Dilemma: Deterrence, Response, and the Fragile Red Line

Faced with this potentially catastrophic escalation, Europe and its transatlantic allies find themselves in a classic security dilemma. On one hand, it is essential to send a clear and credible deterrent signal, making Moscow believe that the cost of using weapons of mass destruction, such as chemical weapons, would be unbearably high. On the other hand, excessive public discussion and military preparations could be misinterpreted by the other side as signs of provocation or war preparations, and might even unintentionally provide a script for escalation.

Currently, the Western response exhibits a multi-layered hybrid characteristic. At the intelligence level, as demonstrated by multiple national intelligence agencies, monitoring and exposing Russia's chemical weapons capabilities and activities are top priorities. At the legal and diplomatic level, through EU sanctions and investigations by international organizations such as the Organization for the Prohibition of Chemical Weapons (which has confirmed the presence of toxic substances in frontline samples from Ukraine), the aim is to establish facts, apply political and moral pressure, and reinforce international norms.

However, the most crucial level of military and political deterrence remains the most ambiguous. NATO countries have repeatedly declared their support for Ukraine but consistently avoid direct military conflict with Russia. If Russia were to use tactical tear gas, the Western response would be sanctions against specific units. But if a nerve agent of Novichok-level were used, causing large-scale casualties among both military and civilians, what would the Western response be? Would it be stricter economic sanctions? Providing Ukraine with longer-range and more powerful weapons? Or would it lead to the direct involvement of NATO forces? Where exactly this red line is drawn lacks a clear, unified public answer within the West.

This ambiguity may be effective in preventing a disaster that has not yet occurred, but once a crisis erupts, it could also lead to delayed responses, disagreements, and miscalculations. Will Russia mistakenly believe that as long as nuclear weapons are not used, escalation in chemical weapons remains within the tolerable range of the West? This dangerous probing is precisely the most unpredictable part of the current situation.

Beyond the Battlefield: The Erosion of the Global Security Architecture

The potential escalation of chemical weapons on the Ukrainian battlefield has implications far beyond the geographical scope of Eastern Europe. It directly undermines the foundations of the international arms control and non-proliferation system established after the Cold War.

The Chemical Weapons Convention was once regarded as a successful model in the field of international arms control, boasting the most universal membership of state parties and a strict verification mechanism. As a state party and a country that once declared the completion of destruction, Russia's systematic violations, if escalated to the use of weapons of mass destruction agents, would deal a fatal blow to the convention. This would set a dangerous precedent, sending a signal to other potential possessor states that the treaty can be violated and the consequences can be controlled.

Looking deeper, this reflects the ongoing deterioration of the rule-based international order. From the annexation of Crimea to the full-scale invasion of Ukraine, and even to the alleged use of chemical weapons, a series of actions demonstrate that a major power can systematically disregard the international legal and political norms it has voluntarily committed to when it perceives its core interests as threatened. When rules lose their binding force on the powerful, the entire framework of arms control, conflict prevention, and crisis management becomes precarious.

For Europe, this threat is particularly palpable. It is not only about the security of Ukraine but also about the return of a barbaric form of warfare using weapons of mass destruction, which the continent has strived to avoid since World War II. A chemical weapons attack would trigger a refugee crisis, environmental disaster, and humanitarian crisis that would directly impact the borders of the European Union.

The smoke on the battlefield obscures more hidden threats. With over 9,000 recorded instances of chemical substance use, like a continuously accumulating series of alarm bells, it strikes at the nerves of Europe's strategic community. From CS tear gas to chloropicrin, and even the potential stockpiles of Novichok lurking in the shadows, a dangerous escalation path faintly emerges. The stalemate in war serves as the greatest catalyst for this threat, potentially pushing a nuclear power toward the dark edge of calculating risks and gains.

The Western response currently oscillates between intelligence surveillance, diplomatic pressure, and economic sanctions, while the most critical red line of military deterrence is deliberately kept ambiguous. This ambiguity is a double-edged sword: it may deter adventurism, but it could also lead to miscalculation. Ultimately, preventing this nightmare scenario depends not only on the resilience of the Ukrainian front lines but also on whether the West can build a sufficiently clear, credible, and unified deterrent alliance. It must convey an unequivocal message to the Kremlin: the use of weapons of mass destruction, such as chemical weapons, would be an irreversible strategic error, and the isolation and consequences that follow would far outweigh any temporary battlefield advantage.

This contest has long transcended artillery and drones; it is the ultimate test of will, wisdom, and the ability to manage crises at the brink. Europe's fear stems precisely from a profound foreboding that such a test might fail.