What is naphtha?

Lake Charles, LA (KPLC) - A Calcasieu Refining Company tank that caught fire Saturday and resulted in a shelter-in-place and evacuation order contained a product called naphtha, but what is naphtha?

Naphtha, which is what the Louisiana State Police confirmed was in the tank, is a generic term applied to a refined or partially refined petroleum fraction. Blended further or mixed with other materials, they make high-grade motor gasoline or jet fuel. They are also used as solvents, petrochemical feedstocks, or as raw materials for the production of town gas.

Because heavy crude oils cannot be transported by pipeline without a reduction of their viscosity, the oils are blended with diluents, such as naphtha. Naphtha is a particularly efficient dilutant and can be recycled from diluted heavy crude after transport and processing.

The Louisiana Department of Environmental Quality told KPLC that air monitoring was conducted throughout the fire in the area, but the monitoring did not find dangerous levels in the air.

Calcasieu Refining Company said, as of Sunday afternoon, air quality monitoring continues to find “non-detect” readings, meaning dangerous levels have not been detected, and they are unaware of any reports of injuries.

Irritation of the eyes and skin, headaches, dizziness, nausea and fatigue are listed as some of the acute health effects that may occur after exposure to naphtha. Chronic effects usually result from repeated exposures to a chemical.

The permissible exposure limit (PEL) for naphtha, which is determined by the U.S. Occupational Safety and Health Administration (OSHA), varies based on the form of the product.

The current OSHA PEL in the workplace for naphtha petroleum distillates is 500 ppm over a 10-hour workday. For coal tar naphtha, the PEL is 100 ppm over a 10-hour workday. The U.S. National Institute for Occupational Safety and Health (NIOSH) offers a recommended exposure limits (REL) for VM & P naphtha at 350 mg/m³.

The CDC website states that around levels of 1000 ppm, which is about 10 times the lower exposure limit, naphtha is immediately dangerous to life and health (IDLH).

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