Mobile Hazards: Why Are These Dangerous Gases Banned from Road Transportation?

I. Preface: “Invisible Bombs” in Road Transportation – Uncontrollable Risks of Dangerous Gases

As a critical link connecting production and consumption, road transportation undertakes the circulation of various materials. However, for dangerous gases, the road environment acts as a “risk amplifier.” Compared with air, railway, and maritime transportation, road transportation features more complex routes (passing through urban core areas, residential zones, farmlands, etc.), more volatile conditions (heavily influenced by weather, road conditions, and traffic flow), and more flexible transport vehicles (with a high proportion of small and medium-sized trucks and inconsistent safety configurations). These characteristics mean that if dangerous gases leak or explode during road transportation, they can easily trigger “small accidents with catastrophic consequences.”

According to the Road Transportation Safety Report for Hazardous Chemicals released by China’s Ministry of Emergency Management in 2024, 186 road transportation accidents involving dangerous gases occurred nationwide over the past three years, resulting in 213 deaths, 387 injuries, and direct economic losses exceeding 1.9 billion yuan. Among these accidents, 85% took place on ordinary highways, with an average impact radius of 1.5 square kilometers, affecting over 2,000 residents. Behind these figures lies a “deadly combination” of the inherent properties of dangerous gases and the unique risks of road transportation. This article will analyze the reasons why these dangerous gases are explicitly banned from road transportation from multiple perspectives, uncovering the safety logic behind these “mobile hazards.”

II. Reason 1: Complex Road Transportation Scenarios Lead to “Unbounded Spread of Hazards” After Leaks

Unlike enclosed air cargo holds or maritime containers, road transportation routes often traverse cities, towns, and villages, passing through densely populated residential areas, schools, hospitals, commercial districts, and ecologically sensitive zones. Once dangerous gases leak, their hazards spread “without boundaries” along the route, posing comprehensive threats to public safety and the environment.

Take hydrogen cyanide, a highly toxic gas, as an example. In 2022, an illegal transportation incident occurred in a province where ordinary trucks were used to transport hydrogen cyanide. When the vehicle passed a suburban residential area, a loose valve on the steel cylinder caused a gas leak. The colorless and odorless hydrogen cyanide quickly spread to nearby communities. Due to a lack of awareness about protective measures among residents, 12 people developed symptoms of poisoning (such as dizziness and vomiting) within just 10 minutes. Two elderly residents lost consciousness immediately due to high-concentration exposure and later died despite rescue efforts. The accident also forced three nearby schools to suspend classes urgently, and all residents within a 500-meter radius were evacuated. Subsequent environmental testing showed that cyanide residues in the soil around the leak site exceeded safety standards by 20 times, requiring six months of professional remediation.

More critically, road transportation routes often intersect with drinking water sources and farmland protection areas. In 2021, a logistics company illegally transported chlorine gas through a highway upstream of a reservoir. A cracked steel cylinder caused a chlorine leak, and some of the gas seeped into the reservoir with rainwater, drastically lowering the water’s pH value. This led to massive fish deaths, disrupted drinking water supply for 10 nearby villages for three days, and contaminated 8 hectares of farmland—directly impacting local agricultural production. This “cross-regional and cross-sectoral spread of hazards” means that accidents involving dangerous gases in road transportation have consequences far beyond the transportation process itself, turning these gases into “mobile pollutants” that threaten public safety and the ecological environment.

III. Reason 2: “Obvious Safety Shortcomings” in Road Transport Vehicles – Inadequate Protection Against Risks

Road transportation of dangerous gases relies on trucks, tankers, and other vehicles. However, some transport vehicles currently suffer from “insufficient safety configurations, irregular modifications, and inadequate maintenance,” resulting in a severe mismatch between their protective capabilities and the high risks of dangerous gases—directly triggering accidents.

In terms of vehicle configurations, compliant dangerous gas transport vehicles must be equipped with explosion-proof compartments, emergency shut-off devices, gas leak detectors, anti-static grounding devices, and other specialized equipment. In reality, however, many illegal operators use ordinary trucks for “unprotected transportation” of dangerous gases to cut costs. In 2023, among illegal dangerous gas transportation cases investigated in a province, 72% of the vehicles lacked leak detectors, 65% had no anti-static grounding straps, and some even used plastic sheets to cover steel cylinders or wire to secure tanks—providing no basic safety protection at all. In a 2022 acetylene gas transportation accident in Jiangsu Province, the involved vehicle was an ordinary box truck with no explosion-proof modifications. During transit, jolts caused the steel cylinders to collide, generating static electricity that ignited the acetylene. The truck was instantly incinerated, and the explosion shockwave damaged three nearby private cars, injuring one pedestrian with flying debris.

In terms of vehicle maintenance, containers such as steel cylinders and tanks for dangerous gas transport require regular pressure tests and airtightness inspections. However, some enterprises skip maintenance to save costs, leaving containers with severe safety hazards. In a 2021 liquid ammonia transportation accident in Shandong Province, the tank of the involved vehicle had been in use for five years beyond its expiration date without any pressure testing. Cracks appeared at the tank’s welds, and when the vehicle traveled downhill, liquid ammonia leaked from these cracks, rapidly vaporizing into a white toxic fog. This obscured the vision of drivers of five following vehicles, triggering a chain-reaction collision that killed four people and injured seven others. These cases prove that the “safety shortcomings” of road transport vehicles turn the “controllable risks” of dangerous gas transportation into “inevitable hazards.” Banning such transportation on roads is a necessary measure to plug these safety loopholes.

IV. Reason 3: “Numerous Uncontrollable Factors” in Road Traffic Environments – High Accident Probability

Road transportation operates in an open traffic environment, influenced by numerous uncontrollable factors such as weather, road conditions, and the behavior of other road users. When combined with the high-risk properties of dangerous gases, these factors significantly increase accident probability, and accidents often occur with “suddenness and unpredictability.”

Extreme weather is the “number one enemy” of road transportation. During summer heatwaves, road surface temperatures can exceed 60℃, causing pressure inside dangerous gas cylinders to rise sharply. When the pressure exceeds the cylinder’s rated capacity, explosions become highly likely. In the summer of 2023, a prolonged heatwave in Henan Province caused a propane gas tanker to explode while in transit. The propane inside the tank expanded due to heat, causing the safety valve to fail. The tanker disintegrated, and explosion debris flew 50 meters away, collapsing two roadside houses and killing three people. Winter cold can increase gas viscosity and freeze valves. In a 2022 liquefied natural gas (LNG) transportation accident in Heilongjiang Province, the vehicle encountered -30℃ temperatures during transit, freezing the tank valve shut. LNG leaked slowly and ignited upon contact with static electricity, burning the vehicle and cracking the road surface—disrupting traffic for 12 hours.

Beyond weather, complex road conditions and traffic violations also raise accident risks. Sharp curves, steep slopes, and narrow bridges on mountain roads; traffic congestion and jaywalking in urban areas; and reckless behaviors such as speeding, lane-switching, and rear-end collisions by other vehicles—all can impact dangerous gas transport vehicles. In a 2024 chlorine gas transportation accident in Hunan Province, a speeding car rear-ended a chlorine tanker, deforming the tank and causing a leak. The car driver died instantly from poisoning. To prevent further harm, the tanker driver urgently drove to an open area, but residents within a 2-kilometer radius still had to be evacuated. These uncontrollable factors make road transportation of dangerous gases like “walking on the edge of a knife”—any minor accident can trigger catastrophic consequences.

V. Reason 4: “High Difficulty in Emergency Response” for Road Transportation – Missing the Optimal Rescue Window

Emergency response to dangerous gas leaks or explosions requires specialized equipment, personnel, and protocols. However, road transportation accidents can occur anywhere randomly, and factors such as traffic jams, narrow roads, and complex surrounding environments delay the arrival of rescue teams. This “time gap” in emergency response allows accident hazards to escalate.

In terms of rescue arrival time, road accidents can occur in remote rural areas or mountainous regions with limited rescue resources. Professional teams (such as hazardous chemical emergency response units or specialized fire brigades) often take 1–2 hours to reach the scene, while the optimal window for handling dangerous gas leaks is typically only 10–30 minutes. In a 2021 hydrogen fluoride gas transportation accident in Yunnan Province, the vehicle overturned on a mountain road, causing a leak. Local township hospital staff arrived first but lacked professional chemical protective suits and neutralizers, leaving them unable to approach the leak site. They could only evacuate residents, and by the time professional rescuers arrived two hours later, the leaked hydrogen fluoride had contaminated nearby water sources and soil—causing more severe environmental damage.

In terms of emergency response sites, accident scenes on urban roads or near residential areas have limited space, making it difficult to deploy large rescue equipment (such as explosion-proof containers or large-scale sewage suction trucks). Additionally, dense populations increase evacuation difficulty. In a 2022 ethylene oxide transportation accident in Shanghai, the vehicle leaked on an urban expressway. As ethylene oxide is flammable and explosive, rescuers first had to close the road and evacuate nearby residents before using explosion-proof equipment to handle the leak. However, heavy traffic on the expressway prolonged the evacuation for one hour, during which ethylene oxide gas spread to nearby office buildings, causing discomfort in some people and increasing response complexity. This “difficulty in reaching the scene and deploying resources” means emergency responses to dangerous gas road accidents are often “inefficient” and even miss the optimal window—further expanding hazards.

VI. Reason 5: “Persistent Illegal Transportation” – Inadequate Regulatory Coverage

Although China has established strict regulations for road transportation of dangerous gases (such as the Regulations on the Safety Management of Hazardous Chemicals and the Provisions on the Administration of Road Transportation of Dangerous Goods), illegal transportation persists due to profit motives. With hidden and covert methods, illegal transportation evades regulation, creating “supervision blind spots” and further amplifying risks.

The concealment of illegal transportation manifests in three main ways:

1. Disguised Transportation: Dangerous gases are disguised as ordinary goods—for example, highly toxic gases are packed in cartons labeled “food additives” or “mechanical parts,” or ordinary liquefied gas cylinders are filled with acetylene or propane to avoid inspection. In 2023, a customs office in Zhejiang Province seized a case where a company attempted to transport potassium cyanide solution via road in cartons labeled “mineral water,” luckily intercepted in time.
2. Night Transportation: Taking advantage of weaker supervision at night, illegal transportation often occurs between 2–5 a.m., using remote routes to reduce inspection risks. In 2022, 80% of illegal dangerous gas transportation cases investigated in a Guangdong region occurred at night, with unmarked vehicles relying on drivers’ experience to avoid detection.
3. Fragmented Transportation: Large quantities of dangerous gases are split into small doses and transported in multiple ordinary vehicles to lower the risk of detection per trip. In a 2021 accident in Sichuan Province, a company split 100kg of chlorine into 20 small steel cylinders and transported them in five ordinary vans. One van leaked, and scattered cylinders made it hard for rescuers to locate all leak points quickly—delaying response time.

From a regulatory perspective, long road routes and numerous checkpoints make “full-route and full-time” supervision impossible relying solely on fixed inspection stations or toll booths. Additionally, remote areas lack monitoring equipment and sufficient supervision personnel. In 2023, only 35% of national illegal dangerous gas transportation cases were detected via road inspections; most were only traced after accidents occurred. This “post-accident supervision” model fails to prevent accidents effectively. When illegal transportation becomes prevalent and regulation cannot deter violations, banning dangerous gases from road transportation becomes an inevitable choice to curb illegal activities and reduce risks at the source.

VII. Reason 6: “Uneven Qualifications” of Road Transport Personnel – Accidents Caused by Operational Errors

Road transportation of dangerous gases requires high professional competence from drivers and escorts, including knowledge of gas properties, emergency response skills, and safety operating procedures. In reality, however, some personnel lack proper qualifications or training, and operational errors have become a “human-induced hazard” triggering accidents.

On one hand, “unqualified personnel” are widespread. To cut costs, some enterprises hire drivers and escorts without hazardous goods transportation qualifications. These individuals lack basic knowledge of dangerous gas safety and may even be unaware of the toxicity or explosion risks of the gases they transport. In a 2022 liquid chlorine transportation accident in Anhui Province, the driver had no hazardous chemical transportation qualification. When a minor leak occurred, he mistakenly identified the leak point as a “loose valve” and forced it shut with a wrench—breaking the valve and causing a large-scale liquid chlorine leak. The driver died from chlorine poisoning, and over 300 nearby residents were affected. On the other hand, even qualified personnel often suffer from “inadequate training.” Some enterprises only focus on obtaining qualifications and neglect regular training, leaving personnel unfamiliar with the properties of new dangerous gases or their emergency response methods. In a 2023 transportation accident involving a new type of fluoride gas in Fujian Province, the escort had not received specialized training for the gas. When a leak occurred, he incorrectly used a water curtain to dilute it (the gas reacts with water to produce highly toxic substances), escalating the hazard and poisoning two rescuers.

Furthermore, fatigued driving and rule violations by transport personnel exacerbate risks. Dangerous gas transport vehicles often require long-distance travel, and some drivers drive continuously for over 10 hours to meet schedules. In a fatigued state, they are prone to operational errors such as sudden braking or sharp turns, causing cylinder collisions or tank shaking. In a 2021 hydrogen transportation accident in Hebei Province, a driver who had been driving for 12 consecutive hours veered off the road due to fatigue and collided with a guardrail. Hydrogen cylinders fell from the vehicle, their valves broke, and the leaked hydrogen ignited upon contact with static electricity—burning the vehicle and closing the road for 8 hours. These “human-induced hazards” further escalate the risks of dangerous gas road transportation, making it a key reason for the ban.

VIII. Reason 7: “Imbalanced Risk-Benefit Ratio” of Road Transportation Compared to Other Modes

Among all transportation methods for dangerous gases, road transportation stands out for its “high risks and low benefits.” Compared with air, railway, and maritime transport, it offers the weakest safety guarantees, while its costs are not significantly lower. From a “risk-benefit balance” perspective, there is no justification for choosing road transportation.

In terms of safety guarantees:

• Air Transport: Follows strict international standards (e.g., IATA Dangerous Goods Regulations) for packaging, loading, and transit, with cargo holds equipped with explosion-proof, fire-fighting, and gas detection systems, and professional crew monitoring.
• Rail Transport: Uses specially designed hazardous goods carriages with fire, explosion, and static protection, and fixed routes with minimal external interference.
• Maritime Transport: Requires rigorous inspection of dangerous goods containers, with ships staffed by professional hazardous materials management teams and emergency equipment.

In contrast, road transportation has far fewer safety measures and is more vulnerable to external factors. Its accident rate is five times that of rail transport and eight times that of air transport.

In terms of costs: Although road transportation has smaller single-trip capacities, its unit cost is not low when accounting for safety configurations, personnel training, and route planning. For example, transporting 10 tons of liquid ammonia via road costs approximately 0.8 yuan per ton-kilometer, compared to 0.6 yuan for rail and 0.5 yuan for short-haul maritime transport. Additionally, road transport incurs higher insurance premiums and penalty risks. A 2023 cost analysis by a chemical enterprise showed that the total cost of road transportation for dangerous gases was 23% higher than rail transport, while safety risks increased several-fold. This “high-risk, low-benefit” imbalance makes road transportation of dangerous gases neither economical nor safe. Banning it is a rational decision based on “cost-risk” considerations.

IX. Reason 8: Severe Social Impacts – Undermining Public Sense of Security and Social Stability

Road transportation accidents involving dangerous gases not only cause casualties and economic losses but also trigger public panic, erode social trust, and even disrupt regional stability. Their “social costs” far exceed the direct losses of the accidents themselves.

In a 2022 hydrogen cyanide leak accident in a province, the incident occurred near a residential area, and delayed information release caused widespread panic among residents. Some rushed to buy gas masks and drinking water, and small-scale gatherings even broke out. The local government had to deploy significant resources to calm public sentiment, taking a week to restore normal social order. After a 2021 chlorine transport accident, property prices in nearby communities dropped by 15% in the short term, and some residents moved away—leading to population loss and declining commercial activity, which had long-term impacts on local socioeconomic development.

Furthermore, such accidents fuel public doubts about government regulatory capabilities, damaging government credibility. In a 2023 explosion caused by illegal dangerous gas transportation, investigations revealed that the enterprise had engaged in long-term illegal activities without being detected. This sparked public dissatisfaction with regulatory authorities, who had to hold multiple press conferences to explain the situation and spent months rebuilding public trust. These “severe social impacts and high remediation costs” make road transportation of dangerous gases an “unbearable burden.” Banning it is an inevitable requirement to maintain social stability and protect public safety.

X. Conclusion: Upholding the Red Line of Road Safety – Cutting the “Spread Chain” of Mobile Hazards

The ban on road transportation of dangerous gases is not a “one-size-fits-all” measure but a scientific decision based on the unique risks of road scenarios, the high hazards of dangerous gases, and the