A systematic approach to identifying, evaluating, and controlling chemical dangers in laboratories and industries
Imagine a typical industrial facility where workers process wood into biofuels. The air is filled with fine wood dust, a common byproduct that seems harmless enough. But on July 29, 2025, at the Horizon Biofuels facility in Fremont, Nebraska, that ordinary dust became the source of a catastrophic explosion that killed three people—an operator and his two young daughters, ages 8 and 12 1 .
"This terrible tragedy should not have happened. Preliminary evidence points to a combustible wood dust explosion, a well-known – and completely avoidable -- hazard in wood processing."
This tragedy exemplifies a fundamental truth in chemical safety: many materials we handle regularly can become deadly under specific conditions. The process of identifying these dangerous scenarios before they occur is what scientists call chemical hazard assessment. It's a systematic approach to recognizing, evaluating, and controlling potential dangers in the world of chemicals—a discipline that stands between routine laboratory work and disaster.
Any inherent source of potential harm or adverse health effect. It's the dangerous capability of a substance or situation.
The combination of the likelihood that a hazard will cause harm and the severity of the consequences.
Before diving into how scientists assess chemical dangers, we need to understand two crucial concepts: hazards and risks.
The risk of being harmed by hydrochloric acid depends on how it's stored, handled, and what protective equipment is used 4 .
One useful model for understanding chemical accidents is the trajectory intersecting model. This theory suggests that accidents occur when two "trajectories" intersect in time and space: unsafe human behaviors and dangerous object conditions 9 .
When a researcher rushes through a procedure (human behavior) while handling a shock-sensitive chemical like TATP (object condition), their trajectories may intersect with catastrophic results. In one 2023 university incident, this exact scenario required the bomb squad to perform a controlled detonation of a laboratory 6 .
Rushing procedures, skipping safety checks
Shock-sensitive chemicals, improper storage
Accident occurs when both factors align
Safety professionals use a systematic approach to quantify risks, often employing a risk matrix that evaluates both the severity of potential consequences and the likelihood of their occurrence .
| Severity of Consequences | Low Probability | Moderate Probability | High Probability |
|---|---|---|---|
| Minor (skin irritation) | Low risk | Low risk | Moderate risk |
| Significant (burns, respiratory damage) | Low risk | Moderate risk | High risk |
| Major (permanent disability) | Moderate risk | High risk | Very high risk |
| Catastrophic (fatality) | Moderate risk | Very high risk | Very high risk |
This matrix helps professionals prioritize which hazards need immediate attention and resources. A chemical with "very high risk" rating would require immediate control measures before any further use .
A 2021 study conducted at five academic laboratories of an Iranian medical sciences university provides an excellent example of how systematic chemical hazard assessment works in practice .
The researchers developed a comprehensive approach with three key phases:
Using structured checklists with 131 specific items, researchers conducted walk-through observations and interviewed laboratory personnel .
Researchers documented all chemicals present, their quantities, storage conditions, and usage patterns .
Each chemical's risk rating was calculated by multiplying "severity" by "likelihood" values .
The assessment revealed significant findings that would be difficult to identify without a systematic approach:
| Hazard Type | Percentage Rated "Moderate" to "Very High" | Most Problematic Chemicals |
|---|---|---|
| Health Hazards |
|
Hydrochloric acid, Nitric acid, Formaldehyde |
| Safety Hazards |
|
Ethanol, Sulfuric acid |
| Environmental Hazards |
|
Hydrochloric acid, Sodium hydroxide |
The research also identified critical system failures contributing to these risks:
While understanding hazards is crucial, controlling them is equally important. Modern laboratories employ multiple layers of protection to ensure safety.
| Safety Item | Primary Function | Key Applications |
|---|---|---|
| Nitrile Gloves | Protection against most chemicals and pathogens | General chemical handling, biological work |
| Lab Coats/Aprons | Barrier protection for skin and clothing | Spill protection, contamination control |
| Safety Goggles | Eye protection from splashes and impacts | Any liquid chemical handling |
| Fume Hoods | Containment and exhaust of hazardous vapors | Volatile chemical procedures |
| Fire Extinguishers | Rapid response to laboratory fires | Emergency response to small fires |
| Safety Data Sheets | Detailed hazard and safety information | Chemical reference, emergency planning |
Properly functioning fume hoods and ventilation systems
Standard operating procedures and safety protocols
Gloves, goggles, lab coats, and respirators
A crucial component of chemical hazard assessment is the Safety Data Sheet (SDS) (formerly Material Safety Data Sheet or MSDS). These technical documents provide comprehensive information about chemical properties, hazards, protective measures, and safety precautions 2 .
Effective chemical safety requires clear communication protocols. These include:
Indicating specific hazards in work areas
"When in doubt, always wear your safety goggles, especially when you are in the lab. Even if you are only working with glassware, you never know—it could break, and you could end up with glass in your eyes, making for a very long day."
The 2025 Horizon Biofuels tragedy reminds us that combustible dust explosions remain a "completely avoidable" hazard 1 . Similarly, the university laboratory incident with TATP production shows how even experienced researchers can inadvertently create dangerous situations 6 .
Transforms safety from luck to a predictable, manageable process
Applies evidence-based evaluation to protect health and environment
Enables innovation to flourish while minimizing risks
What connects these very different scenarios is the constant need for systematic chemical hazard assessment. This process—identifying potential dangers, evaluating their risks, and implementing appropriate controls—forms the foundation of chemical safety. From the simplest teaching laboratory to the most complex industrial facility, the principles remain the same: know your hazards, assess your risks, implement controls, and communicate clearly.
The next time you see a warning label on a chemical container or a researcher wearing safety goggles, remember that these simple visual cues represent an entire ecosystem of safety thinking designed to ensure that we reap the benefits of chemistry without paying the ultimate price.