Si tratta di un kerosene a basso contenuto di zolfo. Questo è quello che ho trovato in rete. Sommandolo alla mia esperienza di chimico credo di poterti dare confermare con buona sicurezza la traduzione come kerosene chiaro o bianco.

The distinction between 1-K and 2-K kerosene fuels cannot be made through visual examination. The terms "water clear" or "clear white" are often used to describe the type of kerosene that can be used in the unvented heater. Although water clear or clear white kerosene may be 1-K in most cases, color should not be used as a sole indicator. The type of crude from which the kerosene is refined, temperature, aging and contamination can all cause kerosene to yellow and become darker. So if the retail dealer does not specifically market the kerosene as the 1-K type of fuel, you should assume the product is not 1-K kerosene. Find a dealer who can certify you are buying 1-K grade kerosene.

Ciao
Bruno