He was asked:

If an impurity, such as a mouse or a similar creature, falls into oil and dies in it, does the oil become impure?

If it is held to become impure, may more liquid be added to it until its volume reaches two qullahs? If such an increase in volume is permissible, may the pure liquid be poured onto the impure liquid, or the reverse, or is there no difference? If increasing its volume is not permissible and the oil is deemed impure, is there any way they may benefit from it, such as using it as lamp fuel or washing it—if it is held that washing purifies it? If small quantities of impure water become pure by adding more water, do other liquids likewise become pure by adding more liquid?

He replied:

Praise be to Allah.

The fundamental question here concerns liquids into which an impurity falls: do they become impure even when their volume is large, exceeding two qullahs? Or are they like water, which, regardless of quantity, becomes impure only if its properties change? Or does a large quantity—such as one reaching two qullahs—become impure only if its properties change?

Three positions are reported from Ahmad on this matter:

The first is that such liquids become impure even in large quantities. This is also the view of al-Shāfi‘ī and others.

The second is that they are like water, whether aqueous or non-aqueous.