What action is prohibited within 25 feet of a HAZMAT railcar?

Smoking is prohibited within 25 feet of a HAZMAT railcar because it poses a significant fire risk in the presence of hazardous materials. Many hazardous substances are flammable or can produce hazardous vapors that ignite easily. The restriction is a critical safety measure to prevent any potential ignition sources that could lead to explosions or fires.

In proximity to HAZMAT railcars, the focus is on maintaining a safe environment to protect not only the crew and first responders but also the surrounding community and environment. Keeping a distance from ignition sources, like open flames or sparks from smoking, is essential in minimizing the risk of accidents and ensuring that hazardous materials are handled safely.

The other options, while they may have specific guidelines or best practices, do not inherently carry the same immediate risk of ignition and are subject to different regulations or protocols.