By Andy May
A leak in an 8-inch pipeline caused 1,300 barrels (roughly 55,000 gallons) of gasoline to spill near Loyalsock Creek, a tributary of the Susquehanna River in Pennsylvania October 21. This has created a huge stir in the media and frothy statements about the evil and dirty oil companies. But, let’s put this and other pipeline spills into perspective. It has been estimated at Johns Hopkins University by Markus Hilpert that between spills at gasoline stations and on-road incidents, 2 metric tonnes of gasoline are spilled every day in the Washington, D.C. area. If other parts of the U.S. spill the same amount per person, then this means 110 metric tonnes of gasoline are spilled by the public every day. 55,000 gallons of gasoline is 1571 metric tonnes, so this is less than 15 days of normal spills from cars across the U.S.
Gasoline does contain small amounts of some toxic substances like benzene, toluene, ethylbenzene and xylenes. Gasoline can also react with air and produce ozone, which some people are sensitive to. However, we are all exposed to these gases every time we fill our cars with gasoline and short term exposure to these fumes in low concentrations (<5 ppm for <15 minutes) has not been shown to have any adverse health effects. This is true regardless of the breathless pronouncements that “there is no safe level of benzene.”
Many regulatory problems arise because a substance can be shown to be harmful in large concentrations and then is over-regulated and the maximum allowable concentration is set too low. This can cause industries to spend large sums for little health and safety benefit. It can even cause industries to go out of business. Think of the coal plants being shut down due to the EPA’s new clean air act.
First, consider some examples of toxic substances that are safe and actually necessary in small doses. Vitamin A is an important nutrient that helps our eyes, helps prevent measles, and can help prevent cancer. But, large doses cause hypervitaminosis A which can cause dizziness, nausea, headaches, skin problems, joint pain, coma and even death. Bananas are radioactive, so are Brazil nuts, but in small doses both are beneficial. So dose matters, small amounts of many dangerous substances cause no harm and may be beneficial, large amounts of the same thing may kill you. One should not fear a dangerous substance, but ask “how much?” Being quantitative is key and often we aren’t.
So, back to refined gasoline. Liquid gasoline is not explosive, particularly flammable or harmful to humans or mammals. Gasoline vapor is very flammable, explosive and toxic. Small amounts of the vapor in the open air, like while filling your car, do not create a health risk. A large spill in an enclosed space, for example a garage, might be harmful and a spark might make the vapors explode. Gasoline is volatile and evaporates very quickly, so even a large amount (for example 55,000 gallons) in the open air will evaporate in a few hours. The vaporous components of gasoline and the portions that remain in water break down very quickly, in hours or days according to the CDC (Center for Disease Control, Agency for Toxic substances). The spill occurred early in the morning of October 21st and between then and October 25th no petroleum related compounds had been detected in the Susquehanna River or at the incoming water at a water plant 27 miles downstream. Monitoring of air quality and water quality by the state environmental agency and the EPA is ongoing. Air monitoring by the Pennsylvania DEP and the US EPA have not detected any hazardous levels of pollutants, but a gasoline “smell” can be detected in some areas, gasoline can be smelled in concentrations as low at 0.25 ppm. Dosage matters.
What about crude oil spills? Crude oil is a natural substance that has been present many places on the surface of the Earth for hundreds of millions of years. A 2003 USGS study has shown that 47% of the crude oil entering the oceans is from natural seeps. Thousands of species of microbes have evolved to eat crude oil and they feast at these sites. Figure 1 shows a natural oil seep near Santa Barbara, California.
Figure 1 (source NOAA)
On land there are also numerous places where oil seeps to the surface, famous seeps like the La Brea Tar pits in California, the Athabasca Oil Sands in Canada, northeastern Oklahoma, and numerous sites in Venezuela have been utilized by humans as medicine, for light or for sealing boats. Natural seeps in Azerbaijan are discussed here. Only the heaviest crude oil components, like asphalt, are not eaten by microbes, which is why asphalt is commonly used to pave roads. Asphalt (or bitumen) is valuable. Besides being used to pave roads it is also used to make shingles for houses. It is a strong binding agent, has a long lifetime and low toxicity. In fact, one World Health Organization study showed that “For job classifications involving bitumen or asphalt exposure, overall mortality was not elevated…” Although, they note a slight increase in lung cancer mortality among road pavers after allowing for a 15-year lag. This suggests a mild toxicity to asphalt fumes when paving roadways.
Crude oil is a complex mixture of hydrocarbons. The more volatile components, like gasoline and kerosene, degrade very quickly, usually within hours. The heavier compounds are mostly eaten by microbes and disappear within a few months. The asphalt or bitumen is what is left. If exposed to oxygen and sunlight, it will decompose; but it can persist for many years in an environment free of oxygen. These deposits of “tar balls” or bitumen can be found anywhere where a natural oil seep exists or after an oil tanker ship wreck or oil-well blowout. Typically, the asphalt is under the surface of the Earth. Just finding a little buried asphalt near an old leak does not mean it came from the leak, it could be natural.
Hydrocarbons on the surface of the Earth are a natural and normal occurrence. But, even so, crude oil or gasoline spills are to be avoided. They are not only messy, but they endanger people and wildlife. We should do all we can to prevent them. According to the U.S. Energy Information Administration, most of our energy in 2040 will still be from refined crude oil or natural gas, see figure 2. Thus, a great deal of crude oil, natural gas, gasoline and diesel will need to be transported to customers between now and then.
Figure 2 (Total Energy used by fuel, DOE_IEA 2016, Fig. MT-19)
The safest and most environmentally friendly way to transport these fluids is by pipeline. Diana Furchtgott-Roth of the Manhattan Institute has shown that pipelines are the best way to transport oil and gas. There are 175,000 miles of petroleum pipelines, 321,000 miles of natural gas pipelines and over 2 million miles of distribution natural gas pipelines to customers and businesses in the U.S. The liquid (both crude oil and refined products) pipelines deliver 70% of petroleum shipments in the U.S. Essentially all natural gas is delivered by pipeline. For liquids, 23% are delivered by tankers and barges, trucks deliver 4% and rail delivers 3%. I refer you to Furchtgott-Roth’s excellent report for the details, but the bottom line is the number of reportable pipeline petroleum liquids incidents per billion ton-miles are only 3% of the truck incidents and only 27% of the rail incidents. The data is from the U.S Department of Transportation and an incident is defined as a spill of over five gallons and/or resulting in an injury. Fatalities per billion ton-miles on roadways due to Hazmat spills are 73 times higher than fatalities due to pipeline incidents. Fatalities due to rail incidents are 25 times those due to pipeline incidents.
While pipeline spills are not the world-ending environmental catastrophes we see portrayed on the television news; they are messy and dangerous. We must do what we can to avoid them. But, produced crude oil and refined products will be delivered to customers, in very large quantities, for the foreseeable future. Pipelines are the most environmentally friendly and the safest way to deliver them, without any doubt.
November 23, 2016