6 
1 Introduction 
In this contribution, only a rough categorization of oil is made into 
light fuel oil 
lubricating oil 
heavy fuel oil 
mixtures (waste oil such as bilge oil, sludge, slops) 
crude oil 
in the context of Oil Spill Identification. 
More detailed information about petroleum and petroleum products can be found in literature. 
Valuable information about product specifications and production techniques is also available 
on the Internet. A detailed description of oil types, including product descriptions, production 
techniques, uses as well as physical and chemical properties is given in a series of product 
dossiers (General Interest Reports) prepared by CONCAWE, Brussels. Most of them (e.g. 
98/109 Heavy Fuel Oils, 95/107 Gas Oils, 97/108 Lubricating Oils) are freely downloadable 
from their server www.concawe.be . 
In Oil Spill Identification by chemical analysis, the identification of the type of oil in a sample 
is essential for several reasons: 
If the origin of an oil pollution is unknown, the investigating authorities must be advised 
on where to find a possible source. In case of a “mystery” spill, the mere differentiation 
between pure, unused products or crude oil and waste oil (bilge residues, sludge, slops) is 
a valuable result. Oils must be identified rapidly in such cases because the chances of 
identifying sources generally decrease with time. 
The meaning of analytical results, i.e. their contribution to the overall evidence in criminal 
proceedings, depends very much on the types of oil that are involved in oil spills. 
Depending on these types, the search can be more or less narrowed down to a few possible 
sources, or even a single one. 
In court trials, the differentiation between pure products and waste oil may be highly 
important because it allows conclusions as to the cause of an oil discharge (technical 
failure, inadvertence, intention). 
It is reasonable to expect the responsible analyst to state with fair certainty that either a light 
fuel oil, lubricating oil, heavy fuel oil, waste oil or crude oil was involved in a particular oil