Few would deny that the oil spill in the Gulf of Mexico was an accident of almost epic proportions – one that cost human lives and whose toll on the environment, wildlife, businesses, and individual livelihoods mounts by the day. So it’s no surprise that the oil industry’s operations have come under increased scrutiny of late. But it turns out that not all oil industry practices carry the same kinds of risks as deepwater drilling. For example, when it comes to transporting its product, the oil industry, for the most part, uses one of the safest modes available: the pipeline.

The first crude oil pipeline was laid in Pennsylvania in 1865. The line was modest – only two inches in diameter and four miles in length – and ran directly from the wellhead to a railroad loading station. This represented a significant advance over the previous practice of transporting oil in wooden kegs loaded on horse-drawn wagons. The success of this new line led to others, and by 1920, U.S. pipeline mileage had tripled. Growth continued at a moderate pace until the early stages of World War II, when 48 U.S. oil tankers were sunk by German submarines. The tankers’ vulnerability quickly led to an expansion of land-based lines moving oil from Texas and Oklahoma to the Eastern Seaboard, and by 1946, there were 140,000 miles of pipeline in the United States, all controlled by oil companies.

Today, there are approximately 200,000 miles of oil pipelines throughout the country, and this $31 billion system moves about two-thirds of the oil transported in the United States. Water carriers move about 28 percent, with motor and rail carriers sharing the remaining 6 percent. To fully appreciate the volume of oil handled through the pipeline system, consider the following: A modest-sized pipeline will transport about 150,000 barrels daily. This volume by road would require 750 tanker trucks daily, delivering a load every two minutes around the clock. Moving it by rail would require a 75-car train, with each tank car carrying 2,000 barrels, arriving and unloading every day.

One of the most important pieces of equipment in the pipeline universe is the pipeline inspection gauge, or pig. During the process of pigging, this tool, the diameter of which matches the diameter of the line, is propelled by the pressure of the product in the pipeline. It is used for several different operations, including the physical separation of different types of liquids, recording geometric information, inspection of walls, and cleaning.

The original pigs were made of straw wrapped in wire and squealed when they moved through the pipe. The term "pipeline inspection gauge" was later created as a backcronym to fit the squealing pig analogy.

Although pipelines can be targets of vandalism or sabotage, the greatest threat to their integrity is damage from excavations. According to the Office of Pipeline Safety, 43 percent of the oil lost from pipelines results from careless digging. The next most common cause of spills is corrosion. To reduce this risk, the pipeline companies have developed a number of technologies, including the pigs. These tools must be utilized, however, to be effective. On Aug. 6, 2006, BP acknowledged that there had been no pig inspection since 1992.

Although many pipelines are 40 to 50 years old, there is no evidence to suggest they represent a significant threat, assuming proper maintenance. This subterranean transportation system, the largest in the world, is recognized as the safest and most economical method of moving huge quantities of oil and gas from production points and refineries to users.