Short answers, pulled from the story.
An oil refinery is an industrial plant that transforms crude oil into usable products including gasoline, diesel fuel, jet fuel, heating oil, kerosene, asphalt, liquefied petroleum gas, and petrochemical feedstocks like ethylene and propylene. Over 6,000 items are made from petroleum by-products, ranging from fertilizer and soap to vitamin capsules and floor coverings.
The first large oil refinery opened at Ploiesti, Romania in 1856-1857. Romania was subsequently registered as the first country in world oil production statistics, according to the Academy of World Records.
Since the 25th of December 2008, the world's largest oil refinery complex has been the Jamnagar Refinery Complex in Gujarat, India, operated by Reliance Industries Limited. It consists of two side-by-side refineries with a combined production capacity of 1.24 million barrels per day.
Lazar Edeleanu, a Romanian chemist of Jewish origin, invented and patented the Edeleanu process in Ploiesti in 1908. He had previously earned his PhD in 1887 by discovering amphetamine. The process improved refining efficiency beyond pure fractional distillation and spread to France, Germany, and the United States within decades.
As of 2014, the United States had 140 operable refineries with a combined capacity of 18.02 million barrels per calendar day. This is down from 301 refineries in 1982, though total capacity has remained roughly comparable due to increases in facility size.
Oil refinery workers face chemical exposures including benzene, toluene, and xylene, with benzene linked to leukemia. Physical hazards include noise levels exceeding 90 decibels, heat reaching 1,600 degrees Fahrenheit in some processes, and risk of explosion. A 2018 US Bureau of Labor Statistics report found refinery workers had an injury rate of 0.4 OSHA-recordable cases per 100 full-time workers, significantly lower than the 3.1 case average across all industries.