Asbestos Exposure in Oil Refineries
An oil refinery is a processing plant where raw crude oil is developed into gasoline, diesel fuel, and other petroleum products. These plants are usually big, rambling complexes connected by extensive pipe works through which fluids are transported to the various processing tanks and storage units.
A Special Kind of Asbestos Product Was Used in Refineries
The type of manufacturing done at an oil refinery releases a number of chemical substances into the air, making it a place that is extremely vulnerable to fire and/or explosion. Many types of asbestos-containing products were used as fire retardants; however the asbestos product that was very heavily used was sprayed limpet asbestos, or limpet, as it was commonly called.
It was developed in England and distributed in a number of countries including the United States. Limpet was made up of 60 percent asbestos, 38 percent cement, and 2 percent mineral oil. Among its uses was as a fireproofing material that was sprayed on steel beams, girders, columns, and beneath flooring; and as a thermal insulation that was sprayed on tanks and turbines. It was also applied to fireproof vessel skirts, stills, and tank storage vessels.
Since routine maintenance at oil refineries is the responsibility of the staff, any type of repair work performed on equipment sprayed with limpet would have exposed these workers to asbestos fibers.
Temperature Control Was Another Important use for Asbestos in Oil Refineries
Cracking coils were heavily insulated with asbestos-containing materials. They are used in the process to break down hydrocarbons into smaller molecules from which products like gasoline are made. The thermal version of this process was performed under temperatures ranging from 450 to 750 degrees Celsius, which is why asbestos was used as a cracking coil insulator because of its ability to withstand high temperatures. In addition, the miles of pipe works in these refineries were typically lined with materials containing 85 percent asbestos and 15 percent magnesia substrate to ensure that hot liquids passing through would not leak.
Asbestos Gaskets Were Another Form of Leakage Protection
Asbestos gaskets were used in piping, valves, and pumps to prevent leakage. There were three types:
- Sheet gaskets – These were 1/8 or 1/16 inch thick compressed asbestos sheets from which the gaskets had to be cut in order to be installed.
- Spiral wound gaskets – This type of gasket contained asbestos filler material compressed between stainless steel spiral windings.
- Meta-jacketed gaskets – These were also made from asbestos filler material, but in this case it was compressed between metal jacketing.
The greatest exposure to asbestos resulted from the cutting of sheet gaskets, which were formed into various sizes in the machine shop onsite at the refinery. Replacing these sheet gaskets also caused significant risk for exposure because sometimes they broke during removal and pieces of the broken gasket remained on either one or both of the seating surfaces. When this happened, the broken pieces would be pried or scrapped off and the seating would then be scrapped or sanded before a new gasket was installed. All of these activities released asbestos fibers into the air if the surfaces were not wetted down.
Refinery Workers Were Also Exposed to Asbestos Through Their Protective Clothing
Asbestos was a component of the protective clothing refinery workers wore to protect them from fire. Damage that resulted from normal wear-and-tear would cause these items to release asbestos fibers into the air to be inhaled.