- Chemical weapons: These are weapons that use chemical agents to cause harm or death. Chemical weapons can be lethal in small doses and can spread over a large area, making them a significant threat. However, chemical weapons are relatively easy to detect and can be neutralized with appropriate protective measures.
- Biological weapons: Biological weapons use microorganisms or toxins to cause disease or death. Biological agents can be highly infectious and can spread quickly, making them a potentially significant threat. However, biological weapons are generally more difficult to produce and disseminate than chemical or nuclear weapons, and effective medical countermeasures (such as vaccines and treatments) are often available.
- Nuclear weapons: These are weapons that use nuclear reactions to produce extremely destructive explosions. Nuclear weapons have the potential to cause catastrophic damage and loss of life, but they are also the most difficult to develop and use. Nuclear weapons require significant resources and expertise to build, and their use would likely lead to severe political consequences.
The United States Department of Homeland Security considers all three of these types of weapons to be potential threats, and it allocates resources based on the perceived level of risk. However, the general consensus among experts is that chemical and nuclear weapons pose a more immediate and significant threat to national security than biological weapons.