The technical definitions for combustible dust vary. In Canada, the Hazardous Products Regulation (WHMIS 2015) defines combustible dust as  a mixture or substance that is in the form of finely divided solid particles that, upon ignition, is liable to catch fire or explode when dispersed in air.
Some rewards from employee incentive contests are exempt from income tax. Such rewards must be tangible personal property, for example, material goods that are for personal use and that are not deductable from the companyâs operating costs. Such rewards are not classified as income, but only up to the value of $1,600.
What does claiming exempt mean for an employeeâs state and local tax liabilities? The federal income tax exemption does not automatically exempt the employee from state or local income taxes. In some states, Form W-4 might or might not exempt the employee from state or local income taxes. The employee might need to fill out a different form for state or local withholding.