An oil refinery accepts crude oil of various grades and distills its components into several products, ranging from propane and gasoline to "bunker oil," which fuels power plants and ocean-going ships. When toxic, flammable material is boiled under pressure, things can go wrong in many different ways, and the results can be disastrous. That's why the safety of workers, the surrounding communities and the environment takes top priority.
Start By Cooking
The simplest refining process heats crude oil in tall stills, the distinctive towers seen at refineries. The most volatile components, such as butane, cook out below 100 degrees Fahrenheit -- cooler than bath water. Jet fuel cooks out beginning around 350 degrees -- just right for roasting a chicken. The last and heaviest "residual" oils cook out at over 1,000 degrees, a temperature high enough to make iron glow. Some refineries distill in a partial vacuum, which allows boiling and distillation at lower temperatures.
A Risky Business From Start to Finish
The original crude oil is already volatile, as seen in spectacular railroad accidents, when tank cars rupture and explode. Aside from explosive elements, the crude oil may also contain toxic sulfur compounds, which can escape as gases. The refining process then sorts out these components into more dangerous products, such as gasoline, and those products have to be captured, moved and stored within the refinery facility. Any failure at any point could cause a release of potentially explosive toxins.
How Things Can Go Wrong
A fire requires fuel, air and heat. All of these are present at a refinery. The air is already everywhere, and the fuel is supposed to be contained in the vessels and pipes of the refinery. An operator error or an equipment malfunction can cause a release. Laws require a routine schedule of inspections, which can identify developing problems, such as corroding pipes. Sometimes the released material will ignite as an explosion or a fire.
It Pays to Be Prepared
Refineries have their own fire and safety crews equipped with protective gear and fire-suppression foam trucks. They're trained to know the materials and processes at the refinery, and how to respond to anything from a vapor cloud to a spill to a fire. They conduct extensive training drills to test themselves and their equipment. Regular site inspections are supposed to spot developing problems before they become emergencies, but sometimes their recommendations are not followed, causing an incident.
Refining in the Regulatory Environment
In the North American Industry Classification System (NAICS), oil refining falls under Oil and Gas Extraction and Processing (NAICS 211). This organizes all of the EPA and OSHA regulations and standards applicable to the industry. Workplace accidents, both major and minor, are reported and investigated. Lessons learned from the investigations -- determinations of exactly what went wrong -- help to guide regulatory development. The American Petroleum Institute maintains a library of standards and statistics.