What color indicates a positive reading on M9 paper?

The color that indicates a positive reading on M9 paper is red. M9 detection paper is used to indicate the presence of certain chemical agents, and it changes color depending on the type of agent detected. When M9 paper comes into contact with a chemical agent, it reacts and changes color; red signifies a positive identification of a nerve or blister agent. Understanding this is critical for personnel to recognize potential threats in a chemical environment and take appropriate safety measures. The other colors—green, yellow, and blue—do not signify a positive detection of these hazardous agents but indicate different types of readings or conditions.