Which color is used on placards to indicate poisonous hazardous materials?

Answer: C — Green

The color green is used on placards to indicate poisonous hazardous materials. This color is part of the coding system established for hazard identification, making it easier for responders and other individuals to quickly recognize the nature of the materials involved in an incident. The green placard signals caution and warns that the materials can pose health risks if inhaled or contacted. Using a distinct color specifically for poisonous materials helps facilitate safety measures during transportation and emergency situations, enhancing the overall management of hazardous materials.