Introduction: 

When it comes to hazardous chemicals used in agriculture and industry, chloropicrin is always on the list. Even though it is banned in the European Union, it continues to be widely used in the United States—especially as a soil fumigant for strawberry crops. The challenge with chloropicrin is that it is both highly effective and highly dangerous. Interestingly, this chemical also has a significant historical background. 

Today, chloropicrin is mainly applied as a fumigant insecticide, nematicide, and antifungal agrochemical. While it offers powerful results in protecting crops, using it without understanding its harmful side effects is extremely risky. Exposure can cause severe irritation to the eyes, nose, and throat. Clearly, it can put workers and nearby communities and even transporters at serious risk if mishandled. 

So, how should we approach such a chemical that is both beneficial and hazardous? This guide will walk you through what chloropicrin is, why it’s still in use despite the dangers, and how it should be handled safely. In short, you’ll find everything you need to know explained in simple, clear language. 

 

What is Chloropicrin? 

Chloropicrin (CCl₃NO₂) is a man-made chemical first synthesized in 1848 by Scottish chemist John Stenhouse. It is a colorless to slightly yellow oily liquid with a strong, irritating smell that makes your eyes water almost instantly. Because of this, it has been called a “tear gas” chemical. 

Its Chemical and Physical Properties 

  • Molecular Weight: 164.37 g/mol 
  • Exact Mass: 162.899461 Da 
  • Heavy Atom Count: 7 
  • Boiling Point: 234 °F at 760 mmHg 
  • Melting Point: -92.6 °F 
  • Solubility: 1 to 5 mg/mL at 72 °F 

 

Historical Connection of Chloropicrin 

It gained major historical attention during World War I. Chloropicrin was used as a chemical warfare agent. Soldiers quickly realized its severe irritating effects once they observed that it caused coughing, vomiting, and tearing, forcing opponents to remove their gas masks, which then made them vulnerable to deadlier chemical agents. 

Although its role in warfare is a dark chapter, chloropicrin’s strong biological activity later led to its use in agriculture. By the early 20th century, scientists discovered that it could effectively control pests, fungi, and nematodes in the soil. From there, its use shifted from a weapon to a tool in farming, particularly as a soil fumigant. It’s used to protect crops like strawberries, tomatoes, and peppers. 

 

Where is Chloropicrin Used Today? 

Agriculture: 

  • Used as a soil fumigant to kill fungi, insects, nematodes, and weeds before planting crops. 
  • Commonly applied to crops like strawberries, peppers, tomatoes, and tobacco. 

Pesticide Mixtures: 

  • Sometimes mixed with other fumigants like methyl bromide or metam sodium. 
  • Acts as a warning agent—its strong odor signals exposure before it reaches lethal levels. 

Laboratory & Industrial Use: 

In rare cases, it is used as a reagent in research or specialty industries. 

 

Why is Chloropicrin Hazardous? 

Here’s what you need to know: 

Health Hazards of Chloropicrin 

Inhalation Risks: 

  • Irritates the nose, throat, and lungs. 
  • Causes coughing, chest pain, and breathing difficulties. 
  • High exposures can lead to pulmonary edema (fluid in the lungs) and long-term lung damage. 

Eye Contact: 

  • Causes intense irritation, tearing, and temporary blindness 
  • In severe cases, it may damage the cornea 

Skin Contact: 

  • The exposure to skin may lead to redness, irritation, and blistering 

Ingestion: 

  • Extremely poisonous if swallowed 
  • Causes severe stomach pain, nausea, vomiting, and internal injury 

 

Environmental Hazards of Chloropicrin 

Chloropicrin doesn’t just affect people. Rather, it can harm the environment too. 

  • Air Drift: During fumigation, it can drift into nearby areas, affecting communities or ecosystems. 
  • Soil Impact: Though used to sterilize soil, improper application may contaminate it. 
  • Water Contamination: If it leaks into groundwater, it can harm aquatic life. 

 

How is Chloropicrin Regulated? 

Given its dangers, chloropicrin is tightly regulated in the U.S. and other countries. 

EPA (Environmental Protection Agency): 

  • Classified as a Restricted-Use Pesticide (RUP). 
  • Only certified applicators with special training are allowed to handle or apply it. 

OSHA (Occupational Safety and Health Administration): 

  • Sets workplace exposure limits. 
  • Employers must provide protective equipment and training. 

DOT (Department of Transportation): 

  • Treats chloropicrin as a hazardous material. 
  • Requires special labeling, packaging, and documentation for transport. 

Label Requirements: 

  • Chloropicrin products must display hazard warnings, protective measures, and emergency instructions. 

 

How Can Workers and Companies Stay Safe? 

To reduce risks, companies handling chloropicrin must have strict safety protocols in place. 

Best Practices for Chloropicrin Safety 

Personal Protective Equipment (PPE): 

  • Full-face respirators with proper filters 
  • Chemical-resistant gloves and protective clothing 

Engineering Controls: 

  • Proper ventilation systems in application areas 
  • Enclosures where possible 

Training & Certification: 

  • Workers must complete EPA-approved fumigation training 
  • Regular safety refreshers are essential 

Emergency Preparedness: 

  • Spill kits and decontamination equipment must be available 
  • Medical support must be accessible on-site 

SDS (Safety Data Sheets): 

  • Updated SDSs must be available at all times. 
  • Workers should be trained to read and understand them. 

 

Why is Chloropicrin Still Used if it’s Harmful? 

Even though chloropicrin is dangerous, it’s still used because of a few strong reasons: 

Effective Pest Control:  

It kills a wide range of soil problems like fungi, insects, and nematodes that harm crops.  

Helps Crop Yield:  

Farmers get higher production, especially for strawberries and other valuable crops, which means better income. 

Limited Alternatives:  

Many safer options are not as effective or are more expensive, so growers continue to rely on chloropicrin. 

Regulations Allow It (in Some Places): 

In the U.S., strict rules control how it’s applied, making it possible to use under certain safety measures. 

Economic Importance:  

Without it, farmers may face huge losses, and some crops might not grow successfully at all. 

Alternatives to Chloropicrin 

With increasing safety and environmental concerns, researchers are exploring safer alternatives: 

  • Biological Soil Treatments (using beneficial microbes) 
  • Soil Solarization (using sunlight to kill pests) 
  • New-generation Fumigants with reduced toxicity 

However, adoption is slow because chloropicrin remains one of the most effective fumigants. 

 

Alternatives to Chloropicrin 

With increasing safety and environmental concerns, researchers are exploring safer alternatives: 

  • Biological Soil Treatments (using beneficial microbes) 
  • Soil Solarization (using sunlight to kill pests) 
  • New-generation Fumigants with reduced toxicity 

However, adoption is slow because chloropicrin remains one of the most effective fumigants. 

 

Conclusion 

Chloropicrin is undeniably powerful, but its hazards cannot be ignored. While it supports modern agriculture, it also poses serious risks to human health and the environment. The bottom line? Safety must come first. Strict protective measures, compliance with regulatory standards, and reliable SDS management are not optional—they are essential. Companies need to treat chemical safety as a responsibility to their workers, communities, and the environment, not just a compliance requirement.