Which background color is used to signify a poisonous substance on a placard?

The correct background color used to signify a poisonous substance on a placard is white. This color is standardized in the communication of hazardous materials, and it serves to alert responders or the public to the nature of the hazard presented by the substance.

In the context of hazardous material transportation and identification, placards serve as a vital visual cue that can quickly inform emergency responders of potential dangers. White is specifically associated with toxic substances in the context of the Hazardous Material Identification System (HMIS) and aligns with the requirements set forth in regulations governing hazardous materials.

Understanding the use of white as a background color is important for ensuring safety and clarity in emergency response situations. This allows first responders to assess risks quickly and take appropriate action when encountering hazardous materials in the field.