Crude oil poses many dangers to the environment because of the injurious effects on ecosystems by the numerous toxic compounds typically found in crude oil. In addition, crude oil can bioaccumulate in wildlife, meaning the toxins are absorbed by virtually all levels of the food chain, says PLOS ONE.
Crude oil is a naturally occurring liquid that consists of hydrocarbons and organic compounds, and it is typically found in underground reservoirs. There are four types of crude oil arranged in Classes A, B, C and D, according to Tox Town from the National Institutes of Health. Class A crude oils are called light, volatile oils because they have a low viscosity; these include jet fuel and gasoline. Class B crude oils are non-sticky, viscous oils; these include diesel fuel and light crude oil. Class C crude oils are highly viscous, sticky oils that pose significant danger to the health of wildlife. Class D crude oils are non-fluid, highly viscous oils and, like Class C oils, pose a significant danger to wildlife.
Crude oil spills account for the majority of crude oil contamination events in ecosystems, explains Larry O'Hanlon for Discovery News. These contamination events expose such animals as microscopic zooplankton, fish, marine mammals, birds and even humans to toxins like benzene, toluene and xylenes. In addition to the immediate dangers of exposure of crude oils to wildlife and humans, there are long-term effects that researchers have yet to fully understand, says The Times-Picayune.