Can naptha be used for bed bugs?

Yes, it can - but you must take serious safety precautions when using it. The suggested amount is one gallon for each 750 cubic feet of space. The room must be sealed tight to prevent the vapor from leaking out. You'll want to focus on areas where the bed bugs are known to congregate - baseboards and skirting, etc (you can use a baster or syringe to get into those areas more efficiently). You need to wear a proper mask with the appropriate filters while applying the naptha. The warmer you can make the room prior to application, the better. You want to try for at least 80 degrees Fahrenheit or higher, if possible. Give the room time to heat adequately, including the walls and ceiling. Before application of the naptha, ensure that there are no open flames - extinguish any fireplaces, furnaces, or other sources of heat. Spray from the top-down - starting with roofing space above the room, if necessary. After application, the room should be left for about 24 hours before ventilating. At that point, simply opening a window for about half an hour is sufficient, as the naptha will dissipate quickly. You'll want to allow the room to continue to ventilate for at least another day, to ensure that there is no concentration remaining. But the room will be safe for re-entry around the 30 minute mark.