As described above, products classified as a HHW have properties that make them inherently dangerous in some way, so they require special consideration for handling and disposal. When HHW is disposed of properly, everyone in the chain of custody knows specifically what products are involved, so the appropriate measures can be taken to prevent accidental releases, exposure, contamination, dangerous reactions, and fires. Putting a HHW in the trash can puts trash collection and handling personnel at risk for injury or even death because they are not aware of the hazardous materials with which they are working. Pouring HHW down the drain, depending on the amount and hazardous characteristics, can affect the efficiency of the public water treatment plant and even damage the biological treatment processes. More importantly, however, is that public water treatment facilities are not designed to destroy most HHW and allow much of it to pass through, thus contaminating the environment.

Proper disposal for HHW is also critical to prevent damage to the environment. Ordinary household trash and HHW may be disposed of by very different methods. Even if the method of disposal seems similar at first sight, the HHW receives greater care in handling and is subject to more stringent requirements during disposal. Landfills fit for ordinary household trash generally are not constructed with the right materials to prevent HHW from escaping into the soil and groundwater. Incinerators designed for ordinary household trash may not have the sophisticated (and more expensive) equipment - incinerator chamber system, stack gas treatment system, and ash collection system - required for HHW. This could allow HHW to remain unburned in the remaining ash or allow hazardous by-products to escape into the air.