Toxicity may arise when two materials are combined in a process even if each is non-toxic separately. This occurs primarily due to which factor?

• A. The chemistry involved
• B. The pressure involved
• C. The temperature involved
• D. None of the above; non-toxic materials will always remain non-toxic when combined

Answer: (A)

The key idea is that toxicity from mixing arises from the chemistry of how the substances interact. When two materials come together, they can react to form new compounds that are toxic, or release toxic gases, heat, or other hazardous energy. Even though each substance may be non-toxic on its own, their reaction products or the conditions created by the reaction can pose a toxic hazard.

Pressure or temperature influence whether and how fast such reactions occur, and can affect the amount or nature of the toxic products formed, but they are not the root cause by themselves. The danger comes from the chemical reactions between the components, not from the mere presence of heat or pressure.