Correct answer: Cost of safe disposal
The greatest expense involves with the use of hazardous materials is the cost of safe disposal of hazardous materials. The hazardous materials may be in the form of liquid, gases or solid. Hazardous waste should not be dumped into the landfills like other waste. It should be incinerated and then it is disposed off underground.
The cost of safe hazardous waste disposal is too high, it cost around $200 to dispose of a 55-gallon drum of hazardous waste.