What is RDX?

RDX, or Research Department Explosive, is a highly powerful nitroamine explosive used in both military and industrial applications. It was developed as a more powerful alternative to TNT during World War II. Also known as cyclonite, hexogen, and T4, RDX has the chemical formula C3H6N6O6. Its chemical name is cyclotrimethylenetrinitramine.

In its pure form, RDX is a white, crystalline solid but is often mixed with other explosives, plasticisers, or it is stable in storage and one of the most powerful military explosives.

RDX does not occur naturally in the environment and can produce harmful fumes when burnt.

What is RDX used for?

• Widely used during World War II in explosive mixtures with TNT, such as Torpex, Composition B, Cyclotols, and H6
• Used in the development of one of the first plastic explosives
• Outside military applications, RDX is also used in controlled demolition to raze structures.

Sources & Routes of Exposure

Sources of Exposure

• Occupational exposure during handling or manufacturing
• Breathing fumes from explosions
• Drinking contaminated water or touching contaminated soil near production or storage facilities
• Eating agricultural crops grown in contaminated soil or irrigated with polluted water

Routes of Exposure

• Inhalation: Minor for the general population; predominant for workers
• Oral: Main route for non-occupational exposure through contaminated drinking water or food
• Dermal: Skin contact during manufacturing

In the Environment

RDX can enter the environment through:

• RDX can be released to the environment through spills, firing of munitions, disposal of ordnance, open incineration and detonation of ordnance, and leaching from inadequately sealed impoundments and demilitarisation of munitions. The compounds can also be released from manufacturing and munitions processing facilities.
• In the atmosphere, RDX is expected to exist in the particulate phase and settle by wet or dry deposition.
• Low soil sorption coefficient (KOC) values indicate that RDX is not significantly retained by most soils and can migrate to groundwater. However, the rate of migration depends on the composition of the soil.
• RDX can migrate through the vadose zone and contaminate underlying groundwater aquifers, especially at source areas that have permeable soils, a shallow groundwater table, and abundant rainfall.
• RDX dissolves slowly in water because of its slow rate of dissolution from the solid phase and does not evapourate from water readily as a result of its low vapour pressure.
• Phototransformation of RDX in soil is not significant; however, it is the primary physical mechanism that degrades RDX in aqueous solutions. Consequently, RDX is not expected to persist for a long period of time in surface waters.
• Based on its low octanol-water partition coefficient (KOW) and low experimental bioconcentration factor, RDX has a low bioconcentration potential in aquatic organisms.
• Results from a study indicate that RDX may bioaccumulate in plants and could be a potential exposure route to herbivorous wildlife.

Health Effects

• Nervous System: Seizures, convulsions, tremors
• Liver: Changes in serum chemistry parameters (not biologically significant)
• Blood Health: Small decreases in erythrocyte and hemoglobin levels
• Classified as a possible human carcinogen by the EPA based on liver tumors in mice

Safety Information

First Aid Measures

• Inhalation: Remove victim to fresh air; loosen clothing; seek medical advice
• Skin Contact: Remove contaminated clothing; wash thoroughly with water; seek medical help
• Eye Contact: Wash eyes immediately with water; seek medical advice
• Ingestion: Rinse mouth, drink water, and seek immediate medical attention

Firefighting Information

• Hazards: Explosive; avoid ignition sources
• Precautions: Evacuate area; allow burning material to burn naturally; do NOT fight fire
• Hazchem Code: E

Exposure Controls & Personal Protection

Engineering Controls

• Maintain adequate ventilation to control air concentrations below exposure limits

Personal Protective Equipment (PPE)

• Wear overalls, safety glasses, and impervious gloves
• Wash hands thoroughly after handling

Regulations

United States

OSHA: The United States Occupational Safety & Health Administration has set the following Permissible Exposure Limit (PEL)for RDX:

Construction Industry: 29 CFR 1926.55 Appendix A -- 1.5 mg/m3 TWA; Skin

Maritime: 29 CFR 1915.1000 Table Z-Shipyards -- 1.5 mg/m3 TWA; Skin

ACGIH: The American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV) for RDX of 0.5 mg/m3 TWA; Skin; Appendix A4 - Not Classifiable as a Human Carcinogen

NIOSH: The National Institute for Occupational Safety and Health (has set a Recommended Exposure Limit (REL) for RDX of 1.5 mg/m3 TWA, 3 mg/m3 STEL; Skin

Australia

Safe Work Australia: Safe Work Australia has set a Time Weighted Average (TWA) concentration for RDX of 1.5 mg/m3 for a 40-hour workweek.