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U.S. Department
of Transportation

Pipeline Safety Stakeholder Communications

Pipeline Safety Connects Us All

Fact Sheet: Products Transported in Pipelines

Below is a listing of products that are transported through pipelines. This listing is not intended to include all products that may be transported via pipelines. Crude oil, refined petroleum products and natural gas make up the vast majority of the volume of products transported through our nation’s pipeline network. However, other gases and petrochemicals may also be transported via pipelines.

Product Hazards

If released into the environment, hydrocarbon liquids (crude oil and refined petroleum products) pose a range of risks to the environment and to human populations. Released petroleum liquids can contaminate ground and surface water resources and harm fragile ecosystems. Hydrocarbon liquids shipped via pipelines generally have vapors that are heavier than air and that will collect in low or enclosed areas. These vapors are simple asphyxiants in that they will displace oxygen and create an oxygen-deficient atmosphere in those areas. In contrast, natural gas is lighter than air and will rise when released. Some other gases transported by pipeline include butane, hydrogen, carbon dioxide (which can also be transported as a liquid), oxygen, and hydrogen sulfide. These gases can be either lighter or heavier than air, but most are asphyxiants in confined spaces. Hydrogen sulfide is a toxic gas and exposure to relatively low concentrations of it can result in death.

Hydrocarbon vapors are flammable or combustible, although different hydrocarbon liquids have different flash points (the temperatures at which sufficient flammable vapors are emitted) and flammable ranges (the range of vapor concentration in air expressed as a percentage by volume). Additionally, many hydrocarbon liquids transported by pipelines have added chemicals that if present in sufficient quantities and concentrations are considered extremely hazardous and sometimes carcinogenic. Exposure to released products may occur via inhalation, ingestion, skin absorption and skin or eye contact.