Toxic naphtha is a quest item used in the Mourning's End Part I quest. It is made by using a sieve on a barrel of naphtha apple mix. The player must use it on a range to turn it into some toxic powder which must then be used as a non-lethal poison to make the residents of West Ardougne ill.
When used on a fire, it will cause a big explosion similar to Nitroglycerin, and will deal damage equal to 75% of your current hitpoints.
