Which of the following is considered a hazardous material?

The correct answer identifies a hazardous material as any substance that poses an unreasonable risk to health, property, or the environment. This definition is crucial for understanding how hazardous materials are classified and managed. Such substances can adversely affect human health through exposure or can cause significant damage to the environment, such as pollution or contamination of water sources.

In contrast, the other options do not align with the established criteria for hazardous materials. A substance that is safe to the environment inherently does not pose a risk, and therefore cannot be classified as hazardous. Similarly, materials that are easily recyclable or food products with no known allergens do not fall under the umbrella of hazardous materials simply because they do not present an unreasonable risk. The focus on "unreasonable risk" is a key component in determining the hazardous nature of a material, emphasizing the potential dangers that certain substances may pose in various contexts.