Machinery Lubrication magazine published by Noria Corporation
Issue link: http://www.e-digitaleditions.com/i/655822
he world of lubrication is filled with many and varied lubri- cant types, and not all of them should be treated in a cavalier manner. In fact, most lubricants should be handled with care and proper personal protective equipment (PPE). The base oils and additives that make up lubricants not only can have cata- strophic effects on the environment, but they can also be toxic to your health. Base Oil Types Base oils are made up of five different groups, as designated by the American Petro- leum Institute (API). These groups help identify base stocks in finished oil formula- tions to ensure the oil's performance criteria are met. Group I includes base oils that are acid- treated, solvent-refined and aromatic. These are lubricants with sufficient evidence of carcinogenicity to humans. Group I oils contain compounds called polycyclic aromatic hydrocarbons (PAHs), which can exist in more than 100 different combinations. PAHs occur naturally in the environment but can also be man-made. They are found in tar, coal and various edible oils. PAHs are impurities that have been left behind after the refining process and are the reason Group I oils are considered carcinogenic. Group ll oils are described as being mildly hydrotreated. While no human data exists for these lubricants, animal data has indicated possible or probable carcinogenicity. Mild hydrotreating helps reduce the amount of carcinogenic PAHs but does not necessarily eliminate them. Increasing the temperature and pressure of hydroprocessing can elimi- nate carcinogenic compounds. Group lll base oils are manufactured using the hydrotreatment process but are subjected to higher temperatures or processing times. These highly hydropro- cessed or non-conventional oils have improved oxidation stability and low-tem- perature performance but still contain some impurities that cannot be removed. These lubricants are not classifiable as being carcinogenic to humans. They include base oils that are severely hydrotreated. The API has classified synthetic engine oils made with polyalphaolefins (PAOs) as a special class of base stock. The term "synthetic" was originally used to refer to Group IV (PAOs) and Group V base stocks. Group IV is used to designate PAO synthetics. All other base stocks, including other synthetics and natural esters (vege- table oils) default into Group V. Of the refining steps used in preparing lubricating oil base stocks from petroleum, only effective solvent extraction, severe hydrogenation or exhaustive fuming sulfuric acid treatment appear to be adequate in eliminating PAHs. Newly synthesized PAOs (Group IV base stocks) do not contain PAHs. With few exceptions, Group V synthetic oils are chemically engineered base stocks that do not fall into any of the previous categories. They are typically esters, poly- glycols and silicone. In this group, most of the attention has been placed on phos- phate esters, which have shown the most potential to harm humans. Allergic reac- tions have been associated with products containing triphenyl phosphate, and a number of health effects have been observed in laboratory animals ingesting phosphate-ester flame retardants. Additives Additives are chemical substances that are mixed within lubricants to enhance their performance. There are many different types of additives, and most have the potential to harm the human body. Some of the more popular additives are shown in SHOULD KNOW About T L u b r i c a n t S t o r a g e a n d H a n d l i n g 46 | March - April 2016 | www.machinerylubrication.com What You LUBRICANT TOXICITY BACK PAGE BASICS mich a el BroW n | Nori a Corpor at ioN A polycyclic aromatic hydrocarbon structure 62% of plants have not taken any steps to address the toxicity and safety concerns in lubricant formulations, based on a recent poll at MachineryLubrication.com