title: Rotherham United F.C.

text: The club's principal sponsor is IPM Group and Asura which features on all the playing kits. The training wear has a separate sponsorship with Guardian Electrical appearing on all training and leisure wear. All kit is made by long term sponsor Puma which has worked with the club for over 10 years.


title: Rotherham United F.C.

text: The club's traditional home was Millmoor in Rotherham where the team played from 1907 to 2008. On one side of the ground is the site of the new Main Stand which remains unfinished. It was hoped that the 4,500 capacity stand which is single tiered, all seated and covered, would be completed sometime during the 2006–07 season, but this had not come to fruition by the time the ground became disused in 2008. On the other side of the ground is the Millmoor Lane Stand, which has a mixture of covered and open seating. Roughly each section on this side is about a third of the length of the pitch. The covered seating in the middle of this stand looks quite distinctive, with several supporting pillars and an arched roof. Both ends are former terraces, with several supporting pillars and have now been made all seated. The larger of the two is the Tivoli End, which was used by home fans. It was noticeable that the pitch slopes up towards this end. The ground also benefits from a striking set of floodlights, the pylons of which are some of the tallest in the country at approximately 124 feet high. Following the failure of the owners of the club and the owners of Millmoor to reach a lease agreement the club left for the Don Valley Stadium in Sheffield in 2008.


title: Rotherham United F.C.

text: Whilst a new purpose-built community stadium was being built in Rotherham, the club relocated to the Don Valley Stadium in nearby Sheffield for four seasons from 2008–09 to 2011–12.


title: Rotherham United F.C.

text: In January 2010 the club announced that their new stadium, later named the AESSEAL New York Stadium, would be built on the former Guest and Chrimes foundry site in Rotherham town centre.


title: Rotherham United F.C.

text: Preparation work on the site began in February 2010 to make way for the foundations to be put in place and for the old factory to be knocked down to make way for the stadium. Construction started in June 2011 and the first game played at the stadium was a pre-season match between Rotherham and Barnsley, held on 21 July 2012. The Millers won 2–1; the first goal in the stadium was scored by Jacob Mellis of Barnsley, and David Noble scored Rotherham's first goal in their new home. The New York Stadium made its league debut on 18 August 2012, in which Rotherham beat Burton Albion 3–0,


title: Rotherham United F.C.

text: Millers’ supporters consider Sheffield Wednesday to be the clubs main rival, Wednesday's home ground - Hillsborough Stadium is the closest stadium to Rotherham United’s, The New York Stadium.


title: Rotherham United F.C.

text: Rotherham United also hold strong rivalries with fellow South Yorkshire clubs Doncaster Rovers and Sheffield United


title: Rotherham United F.C.

text: Rotherham also have dislike to near side North Derbyshire club Chesterfield FC, with the rivalry between the Spireites and the Millers intensifying in the late 2000s and early 2010s.


title: Rotherham United F.C.

text: In the TV series ChuckleVision, there are often references made to the club, whom the brothers support in real life. In "Football Heroes", Paul and Barry play for Rotherham after a mix-up with two former players of the club, Paul scores an own-goal and thinking it was a genuine goal, celebrates with Barry.


title: Chagas disease

text: Chagas disease, also known as American trypanosomiasis, is a tropical parasitic disease caused by "Trypanosoma cruzi". It is spread mostly by insects in the subfamily "Triatominae", known as "kissing bugs". The symptoms change over the course of the infection. In the early stage, symptoms are typically either not present or mild, and may include fever, swollen lymph nodes, headaches, or swelling at the site of the bite. After four to eight weeks, untreated individuals enter the chronic phase of disease, which in most cases does not result in further symptoms. Up to 45% of people with chronic infections develop heart disease 10–30 years after the initial illness, which can lead to heart failure. Digestive complications, including an enlarged esophagus or an enlarged colon, may also occur in up to 21% of people, and up to 10% of people may experience nerve damage.


title: Chagas disease

text: Prevention focuses on eliminating kissing bugs and avoiding their bites. This may involve the use of insecticides or bed-nets. Other preventive efforts include screening blood used for transfusions. , a vaccine has not been developed. Early infections are treatable with the medications benznidazole or nifurtimox, which usually cure the disease if given shortly after the person is infected, but become less effective the longer a person has had Chagas disease. When used in chronic disease, medication may delay or prevent the development of end-stage symptoms. Benznidazole and nifurtimox often cause side effects, including skin disorders, digestive system irritation, and neurological symptoms, which can result in treatment being discontinued. , new drugs for Chagas disease are under development, and experimental vaccines have been studied in animal models.


title: Chagas disease

text: It is estimated that 6.5 million people, mostly in Mexico, Central America and South America, have Chagas disease as of 2019, resulting in approximately 9,490 annual deaths. Most people with the disease are poor, and most do not realize they are infected. Large-scale population migrations have carried Chagas disease to new regions, which include the United States and many European countries. The disease affects more than 150 types of animals.


title: Chagas disease

text: The disease was first described in 1909 by Brazilian physician Carlos Chagas, after whom it is named. Chagas disease is classified as a neglected tropical disease.


title: Chagas disease

text: Chagas disease occurs in two stages: an acute stage, which develops one to two weeks after the insect bite, and a chronic stage, which develops over many years. The acute stage is often symptom-free. When present, the symptoms are typically minor and not specific to any particular disease. Signs and symptoms include fever, malaise, headache, and enlargement of the liver, spleen, and lymph nodes. Sometimes, people develop a swollen nodule at the site of infection, which is called "Romaña's sign" if it is on the eyelid, or a "chagoma" if it is elsewhere on the skin. In rare cases (less than 1–5%), infected individuals develop severe acute disease, which can involve inflammation of the heart muscle, fluid accumulation around the heart, and inflammation of the brain and surrounding tissues, and may be life-threatening. The acute phase typically lasts four to eight weeks and resolves without treatment.


title: Chagas disease

text: Unless treated with antiparasitic drugs, individuals remain infected with after recovering from the acute phase. Most chronic infections are asymptomatic, which is referred to as "indeterminate" chronic Chagas disease. However, over decades with the disease, approximately 30–40% of people develop organ dysfunction ("determinate" chronic Chagas disease), which most often affects the heart or digestive system.


title: Chagas disease

text: The most common long-term manifestation is heart disease, which occurs in 14–45% of people with chronic Chagas disease. People with Chagas heart disease often experience heart palpitations, and sometimes fainting, due to irregular heart function. By electrocardiogram, people with Chagas heart disease most frequently have arrhythmias. As the disease progresses, the heart's ventricles become enlarged (dilated cardiomyopathy), which reduces its ability to pump blood. In many cases the first sign of Chagas heart disease is heart failure, thromboembolism, or chest pain associated with abnormalities in the microvasculature.


title: Chagas disease

text: Also common in chronic Chagas disease is damage to the digestive system, which affects 10–21% of people. Enlargement of the esophagus or colon are the most common digestive issues. Those with enlarged esophagus often experience pain (odynophagia) or trouble swallowing (dysphagia), acid reflux, cough, and weight loss. Individuals with enlarged colon often experience constipation, and may develop severe blockage of the intestine or its blood supply. Up to 10% of chronically infected individuals develop nerve damage that can result in numbness and altered reflexes or movement. While chronic disease typically develops over decades, some individuals with Chagas disease (less than 10%) progress to heart damage directly after acute disease.


title: Chagas disease

text: Signs and symptoms differ for people infected with through less common routes. People infected through ingestion of parasites tend to develop severe disease within three weeks of consumption, with symptoms including fever, vomiting, shortness of breath, cough, and pain in the chest, abdomen, and muscles. Those infected congenitally typically have few to no symptoms, but can have mild non-specific symptoms, or severe symptoms such as jaundice, respiratory distress, and heart problems. People infected through organ transplant or blood transfusion tend to have symptoms similar to those of vector-borne disease, but the symptoms may not manifest for anywhere from a week to five months. Chronically infected individuals who become immunosuppressed due to HIV infection can have particularly severe and distinct disease, most commonly characterized by inflammation in the brain and surrounding tissue or brain abscesses. Symptoms vary widely based on the size and location of brain abscesses, but typically include fever, headaches, seizures, loss of sensation, or other neurological issues that indicate particular sites of nervous system damage. Occasionally, these individuals also experience acute heart inflammation, skin lesions, and disease of the stomach, intestine, or peritoneum.


title: Chagas disease

text: Chagas disease is caused by infection with the protozoan parasite , which is typically introduced into humans through the bite of triatomine bugs, also called "kissing bugs". When the insect defecates at the bite site, motile forms called trypomastigotes enter the bloodstream and invade various host cells. Inside a host cell, the parasite transforms into a replicative form called an amastigote, which undergoes several rounds of replication. The replicated amastigotes transform back into trypomastigotes, which burst the host cell and are released into the bloodstream. Trypomastigotes then disseminate throughout the body to various tissues, where they invade cells and replicate. Over many years, cycles of parasite replication and immune response can severely damage these tissues, particularly the heart and digestive tract.


title: Chagas disease

text: "T. cruzi" can be transmitted by various triatomine bugs in the genera "Triatoma", "Panstrongylus", and "Rhodnius". The primary vectors for human infection are the species of triatomine bugs that inhabit human dwellings, namely "Triatoma infestans", "Rhodnius prolixus", "Triatoma dimidiata" and "Panstrongylus megistus". These insects are known by a number of local names, including "vinchuca" in Argentina, Bolivia, Chile and Paraguay, "barbeiro" (the barber) in Brazil, "pito" in Colombia, "chinche" in Central America, and "chipo" in Venezuela. The bugs tend to feed at night, preferring moist surfaces near the eyes or mouth. A triatomine bug can become infected with when it feeds on an infected host. replicates in the insect's intestinal tract and is shed in the bug's feces. When an infected triatomine feeds, it pierces the skin and takes in a blood meal, defecating at the same time to make room for the new meal. The bite is typically painless, but causes itching. Scratching at the bite introduces the -laden feces into the bite wound, initiating infection.


title: Chagas disease

text: In addition to classical vector spread, Chagas disease can be transmitted through consumption of food or drink contaminated with triatomine insects or their feces. Since heating or drying kills the parasites, drinks and especially fruit juices are the most frequent source of infection. This oral route of transmission has been implicated in several outbreaks, where it led to unusually severe symptoms, likely due to infection with a higher parasite load than from the bite of a triatomine bug.


title: Chagas disease

text: "T. cruzi" can be transmitted independent of the triatomine bug during blood transfusion, following organ transplantation, or across the placenta during pregnancy. Transfusion with the blood of an infected donor infects the recipient 10–25% of the time. To prevent this, blood donations are screened for in many countries with endemic Chagas disease, as well as the United States. Similarly, transplantation of solid organs from an infected donor can transmit to the recipient. This is especially true for heart transplant, which transmits "T. cruzi" 75–100% of the time, and less so for transplantation of the liver (0–29%) or a kidney (0–19%). An infected mother can pass to her child through the placenta; this occurs in up to 15% of births by infected mothers. As of 2019, 22.5% of new infections occurred through congenital transmission.


title: Chagas disease

text: In the acute phase of the disease, signs and symptoms are caused directly by the replication of and the immune system's response to it. During this phase, can be found in various tissues throughout the body and circulating in the blood. During the initial weeks of infection, parasite replication is brought under control by production of antibodies and activation of the host's inflammatory response, particularly cells that target intracellular pathogens such as NK cells and macrophages, driven by inflammation-signaling molecules like TNF-α and IFN-γ.


title: Chagas disease

text: During chronic Chagas disease, long-term organ damage develops over years due to continued replication of the parasite and damage from the immune system. Early in the course of the disease, is found frequently in the striated muscle fibers of the heart. As disease progresses, the heart becomes generally enlarged, with substantial regions of cardiac muscle fiber replaced by scar tissue and fat. Areas of active inflammation are scattered throughout the heart, with each housing inflammatory immune cells, typically macrophages and T cells. Late in the disease, parasites are rarely detected in the heart, and may be present at only very low levels.


title: Chagas disease

text: In the heart, colon, and esophagus, chronic disease leads to a massive loss of nerve endings. In the heart, this may contribute to arrythmias and other cardiac dysfunction. In the colon and esophagus, loss of nervous system control is the major driver of organ dysfunction. Loss of nerves impairs the movement of food through the digestive tract, which can lead to blockage of the esophagus or colon and restriction of their blood supply.


title: Chagas disease

text: The presence of "T. cruzi" in the blood is diagnostic of Chagas disease. During the acute phase of infection, it can be detected by microscopic examination of fresh anticoagulated blood, or its buffy coat, for motile parasites; or by preparation of thin and thick blood smears stained with Giemsa, for direct visualization of parasites. Blood smear examination detects parasites in 34–85% of cases. The sensitivity increases if techniques such as microhematocrit centrifugation are used to concentrate the blood. On microscopic examination of stained blood smears, trypomastigotes appear as S or U-shaped organisms with a flagellum connected to the body by an undulating membrane. A nucleus and a smaller structure called a kinetoplast are visible inside the parasite's body; the kinetoplast of is relatively large, which helps to distinguish it from other species of trypanosomes that infect humans.


title: Chagas disease

text: Alternatively, "T. cruzi" DNA can be detected by polymerase chain reaction (PCR). In acute and congenital Chagas disease, PCR is more sensitive than microscopy, and it is more reliable than antibody-based tests for the diagnosis of congenital disease because it is not affected by transfer of antibodies against from a mother to her baby (passive immunity). PCR is also used to monitor levels in organ transplant recipients and immunosuppressed people, which allows infection or reactivation to be detected at an early stage.


title: Chagas disease

text: In chronic Chagas disease, the concentration of parasites in the blood is too low to be reliably detected by microscopy or PCR, so the diagnosis is usually made using serological tests, which detect immunoglobulin G antibodies against in the blood. Two positive serology results, using different test methods, are required to confirm the diagnosis. If the test results are inconclusive, additional testing methods such as Western blot can be used.


title: Chagas disease

text: Various rapid diagnostic tests for Chagas disease are available. These tests are easily transported and can be performed by people without special training. They are useful for screening large numbers of people and testing people who cannot access healthcare facilities, but their sensitivity is relatively low, and it is recommended that a second method is used to confirm a positive result.


title: Chagas disease

text: "T. cruzi" parasites can be grown from blood samples by blood culture, xenodiagnosis, or by inoculating animals with the person's blood. In the blood culture method, the person's red blood cells are separated from the plasma and added to a specialized growth medium to encourage multiplication of the parasite. It can take up to six months to obtain the result. Xenodiagnosis involves feeding the blood to triatomine insects, then examining their feces for the parasite 30 to 60 days later. These methods are not routinely used, as they are slow and have low sensitivity.


title: Chagas disease

text: Efforts to prevent Chagas disease have largely focused on vector control to limit exposure to triatomine bugs. Insecticide-spraying programs have been the mainstay of vector control, consisting of spraying homes and the surrounding areas with residual insecticides. This was originally done with organochlorine, organophosphate, and carbamate insecticides, which were supplanted in the 1980s with pyrethroids. These programs have drastically reduced transmission in Brazil and Chile, and eliminated major vectors from certain regions: "Triatoma infestans" from Brazil, Chile, Uruguay, and parts of Peru and Paraguay, as well as "Rhodnius prolixus" from Central America. Vector control in some regions has been hindered by the development of insecticide resistance among triatomine bugs. In response, vector control programs have implemented alternative insecticides (e.g. fenitrothion and bendiocarb in Argentina and Bolivia), treatment of domesticated animals (which are also fed on by triatomine bugs) with pesticides, pesticide-impregnated paints, and other experimental approaches. In areas with triatomine bugs, transmission of can be prevented by sleeping under bed nets and by housing improvements that prevent triatomine bugs from colonizing houses.


title: Chagas disease

text: Blood transfusion was formerly the second-most common mode of transmission for Chagas disease. can survive in refrigerated stored blood, and can survive freezing and thawing, allowing it to persist in whole blood, packed red blood cells, granulocytes, cryoprecipitate, and platelets. The development and implementation of blood bank screening tests has dramatically reduced the risk of infection during blood transfusion. Nearly all blood donations in Latin American countries undergo Chagas screening. Widespread screening is also common in non-endemic nations with significant populations of immigrants from endemic areas, including the United Kingdom (implemented in 1999), Spain (2005), the United States (2007), France and Sweden (2009), Switzerland (2012), and Belgium (2013). Serological tests, typically ELISAs, are used to detect antibodies against proteins in donor blood.


title: Chagas disease

text: Other modes of transmission have been targeted by Chagas disease prevention programs. Treating -infected mothers during pregnancy reduces the risk of congenital transmission of the infection. To this end, many countries in Latin America have implemented routine screening of pregnant women and infants for infection, and the World Health Organization recommends screening all children born to infected mothers to prevent congenital infection from developing into chronic disease. Similarly to blood transfusions, many countries with endemic Chagas disease screen organs for transplantation with serological tests.


title: Chagas disease

text: There is no vaccine against Chagas disease. Several experimental vaccines have been tested in animals infected with and were able to reduce parasite numbers in the blood and heart, but no vaccine candidates had undergone clinical trials in humans as of 2016.


title: Chagas disease

text: Chagas disease is managed using antiparasitic drugs to eliminate "T. cruzi" from the body, and symptomatic treatment to address the effects of the infection. As of 2018, benznidazole and nifurtimox were the antiparasitic drugs of choice for treating Chagas disease, though benznidazole is the only drug available in most of Latin America. For either drug, treatment typically consists of two to three oral doses per day for 60 to 90 days. Antiparasitic treatment is most effective early in the course of infection: it eliminates from 50 to 80% of people in the acute phase, but only 20–60% of those in the chronic phase. Treatment of chronic disease is more effective in children than in adults, and the cure rate for congenital disease approaches 100% if treated in the first year of life. Antiparasitic treatment can also slow the progression of the disease and reduce the possibility of congenital transmission. Elimination of does not cure the cardiac and gastrointestinal damage caused by chronic Chagas disease, so these conditions must be treated separately. Antiparasitic treatment is not recommended for people who have already developed dilated cardiomyopathy.


title: Chagas disease

text: Benznidazole is usually considered the first-line treatment because it has milder adverse effects than nifurtimox, and its efficacy is better understood. Both benznidazole and nifurtimox have common side effects that can result in treatment being discontinued. The most common side effects of benznidazole are skin rash, digestive problems, decreased appetite, weakness, headache, and sleeping problems. These side effects can sometimes be treated with antihistamines or corticosteroids, and are generally reversed when treatment is stopped. However, benzidazole is discontinued in up to 29% of cases. Nifurtimox has more frequent side effects, affecting up to 97.5% of individuals taking the drug. The most common side effects are loss of appetite, weight loss, nausea and vomiting, and various neurological disorders including mood changes, insomnia, paresthesia and peripheral neuropathy. Treatment is discontinued in up to 75% of cases. Both drugs are contraindicated for use in pregnant women and people with liver or kidney failure. As of 2019, resistance to these drugs has been reported.


title: Chagas disease

text: In the chronic stage, treatment involves managing the clinical manifestations of the disease. The treatment of Chagas cardiomyopathy is similar to that of other forms of heart disease. Beta blockers and ACE inhibitors may be prescribed, but some people with Chagas disease may not be able to take the standard dose of these drugs because they have low blood pressure or a low heart rate. To manage irregular heartbeats, people may be prescribed anti-arrhythmic drugs such as amiodarone, or have a pacemaker implanted. Blood thinners may be used to prevent thromboembolism and stroke. Chronic heart disease caused by Chagas is a common reason for heart transplantation surgery. Because transplant recipients take immunosuppressive drugs to prevent organ rejection, they are monitored using PCR to detect reactivation of the disease. People with Chagas disease who undergo heart transplantation have higher survival rates than the average heart transplant recipient.


title: Chagas disease

text: Mild gastrointestinal disease may be treated symptomatically, such as by using laxatives for constipation, or taking a prokinetic drug like metoclopramide before meals to relieve esophageal symptoms. Surgery to sever the muscles of the lower esophageal sphincter (cardiomyotomy) may be performed in more severe cases of esophageal disease, and surgical removal of the affected part of the organ may be required for advanced megacolon and megaesophagus.


title: Chagas disease

text: In 2019, an estimated 6.5 million people worldwide had Chagas disease, with approximately 173,000 new infections and 9,490 deaths each year. The disease resulted in a global annual economic burden estimated at US$7.2 billion in 2013, 86% of which is borne by endemic countries. Chagas disease results in the loss of over 800,000 disability-adjusted life years each year.


title: Chagas disease

text: The endemic area of Chagas disease stretches from the southern United States to northern Chile and Argentina, with Bolivia (6.1%), Argentina (3.6%), and Paraguay (2.1%) exhibiting the highest prevalence of the disease. Within continental Latin America, Chagas disease is endemic to 21 countries: Argentina, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Uruguay, and Venezuela. In endemic areas, due largely to vector control efforts and screening of blood donations, annual infections and deaths have fallen by 67% and more than 73% respectively from their peaks in the 1980s to 2010. Transmission by insect vector and blood transfusion has been completely interrupted in Uruguay (1997), Chile (1999), and Brazil (2006), and in Argentina, vectorial transmission had been interrupted in 13 of the 19 endemic provinces as of 2001. During Venezuela's humanitarian crisis, vectorial transmission has begun occurring in areas where it had previously been interrupted, and Chagas disease seroprevalence rates have increased. Transmission rates have also risen in the Gran Chaco region due to insecticide resistance and in the Amazon basin due to oral transmission.


title: Chagas disease

text: While the rate of vector-transmitted Chagas disease has declined throughout most of Latin America, the rate of orally transmitted disease has risen, possibly due to increasing urbanization and deforestation bringing people into closer contact with triatomines and altering the distribution of triatomine species. Orally transmitted Chagas disease is of particular concern in Venezuela, where 16 outbreaks have been recorded between 2007 and 2018.


title: Chagas disease

text: Chagas exists in two different ecological zones: In the Southern Cone region, the main vector lives in and around human homes. In Central America and Mexico, the main vector species lives both inside dwellings and in uninhabited areas. In both zones, Chagas occurs almost exclusively in rural areas, where also circulates in wild and domestic animals. commonly infects more than 100 species of mammals across Latin America including opossums ("Didelphis" spp.), armadillos, marmosets, bats, various rodents and dogs all of which can be infected by the vectors or orally by eating triatomine bugs and other infected animals. For entomophagous animals this is a common mode. "Didelphis" spp. are unique in that they do not require the triatomine for transmission, completing the life cycle through their own urine and feces. Veterinary transmission also occurs through vertical transmission through the placenta, blood transfusion and organ transplants.


title: Chagas disease

text: Though Chagas is traditionally considered a disease of rural Latin America, international migration has dispersed those with the disease to numerous non-endemic countries, primarily in North America and Europe. As of 2020, approximately 300,000 infected people are living in the United States, and in 2018 it was estimated that 30,000 to 40,000 Americans had Chagas cardiomyopathy. The vast majority of cases in the United States occur in immigrants from Latin America, but local transmission is possible. Eleven triatomine species are native to the United States, and some southern states have persistent cycles of disease transmission between insect vectors and animal reservoirs, which include woodrats, possums, raccoons, armadillos and skunks. However, locally acquired infection is very rare: only 28 cases were documented from 1955 to 2015. As of 2013, the cost of treatment in the United States was estimated to be US$900 million annually (global cost $7 billion), which included hospitalization and medical devices such as pacemakers.


title: Chagas disease

text: Chagas disease affects approximately 68,000 to 123,000 people in Europe as of 2019. Spain, which has a high rate of immigration from Latin America, has the highest prevalence of the disease. It is estimated that 50,000 to 70,000 Spanish people are living with Chagas disease, accounting for the majority of European cases. The prevalence varies widely within European countries due to differing immigration patterns. Italy has the second highest prevalence, followed by the Netherlands, the United Kingdom, and Germany.


title: Chagas disease

text: "T. cruzi" likely circulated in South American mammals long before the arrival of humans on the continent. has been detected in ancient human remains across South America, from a 9000-year-old Chinchorro mummy in the Atacama Desert, to remains of various ages in Minas Gerais, to an 1100-year-old mummy as far north as the Chihuahuan Desert near the Rio Grande. Many early written accounts describe symptoms consistent with Chagas disease, with early descriptions of the disease sometimes attributed to Miguel Diaz Pimenta (1707), (1735), and Theodoro J. H. Langgaard (1842).


title: Chagas disease

text: The formal description of Chagas disease was made by Carlos Chagas in 1909 after examining a two-year-old girl with fever, swollen lymph nodes, and an enlarged spleen and liver. Upon examination of her blood, Chagas saw trypanosomes identical to those he had recently identified from the hindgut of triatomine bugs and named "Trypanosoma cruzi" in honor of his mentor, Brazilian physician Oswaldo Cruz. He sent infected triatomine bugs to Cruz in Rio de Janeiro, who showed the bite of the infected triatomine could transmit to marmoset monkeys as well. In just two years, 1908 and 1909, Chagas published descriptions of the disease, the organism that caused it, and the insect vector required for infection. Almost immediately thereafter, at the suggestion of Miguel Couto, then professor of the , the disease was widely referred to as "Chagas disease". Chagas' discovery brought him national and international renown, but in highlighting the inadequacies of the Brazilian government's response to the disease, Chagas attracted criticism to himself and to the disease that bore his name, stifling research on his discovery and likely frustrating his nomination for the Nobel Prize in 1921.


title: Chagas disease

text: In the 1930s, Salvador Mazza rekindled Chagas disease research, describing over a thousand cases in Argentina's Chaco Province. In Argentina, the disease is known as "mal de Chagas-Mazza" in his honor. Serological tests for Chagas disease were introduced in the 1940s, demonstrating that infection with was widespread across Latin America. This, combined with successes eliminating the malaria vector through insecticide use, spurred the creation of public health campaigns focused on treating houses with insecticides to eradicate triatomine bugs. The 1950s saw the discovery that treating blood with crystal violet could eradicate the parasite, leading to its widespread use in transfusion screening programs in Latin America. Large-scale control programs began to take form in the 1960s, first in São Paulo, then various locations in Argentina, then national-level programs across Latin America. These programs received a major boost in the 1980s with the introduction of pyrethroid insecticides, which did not leave stains or odors after application and were longer-lasting and more cost-effective. Regional bodies dedicated to controlling Chagas disease arose through support of the Pan American Health Organization, with the Initiative of the Southern Cone for the Elimination of Chagas Diseases launching in 1991, followed by the Initiative of the Andean countries (1997), Initiative of the Central American countries (1997), and the Initiative of the Amazon countries (2004).


title: Chagas disease

text: Fexinidazole, an antiparasitic drug approved for treating African trypanosomiasis, has shown activity against Chagas disease in animal models. As of 2019, it is undergoing phase II clinical trials for chronic Chagas disease in Spain. Other drug candidates include GNF6702, a proteasome inhibitor that is effective against Chagas disease in mice and is undergoing preliminary toxicity studies, and AN4169, which has had promising results in animal models.


title: Chagas disease

text: A number of experimental vaccines have been tested in animals. In addition to subunit vaccines, some approaches have involved vaccination with attenuated parasites or organisms that express some of the same antigens as but do not cause human disease, such as "Trypanosoma rangeli" or "Phytomonas serpens". DNA vaccination has also been explored. As of 2019, vaccine research has mainly been limited to small animal models.


title: Chagas disease

text: As of 2018, standard diagnostic tests for Chagas disease were limited in their ability to measure the effectiveness of antiparasitic treatment, as serological tests may remain positive for years after is eliminated from the body, and PCR may give false-negative results when the parasite concentration in the blood is low. Several potential biomarkers of treatment response are under investigation, such as immunoassays against specific antigens, flow cytometry testing to detect antibodies against different life stages of , and markers of physiological changes caused by the parasite, such as alterations in coagulation and lipid metabolism.


title: Chagas disease

text: Another research area is the use of biomarkers to predict the progression of chronic disease. Serum levels of tumor necrosis factor alpha, brain and atrial natriuretic peptide, and angiotensin-converting enzyme 2 have been studied as indicators of the prognosis of Chagas cardiomyopathy.


title: Chagas disease

text: "T. cruzi" shed acute-phase antigen (SAPA), which can be detected in blood using ELISA or Western blot, has been used as an indicator of early acute and congenital infection. An assay for antigens in urine has been developed to diagnose congenital disease.


title: Plus and minus signs

text: The plus and minus signs, and , are mathematical symbols used to represent the notions of positive and negative, respectively. In addition, represents the operation of addition, which results in a sum, while represents subtraction, resulting in a difference. Their use has been extended to many other meanings, more or less analogous. "Plus" and "minus" are Latin terms meaning "more" and "less", respectively.


title: Plus and minus signs

text: Though the signs now seem as familiar as the alphabet or the Hindu-Arabic numerals, they are not of great antiquity. The Egyptian hieroglyphic sign for addition, for example, resembled a pair of legs walking in the direction in which the text was written (Egyptian could be written either from right to left or left to right), with the reverse sign indicating subtraction:


title: Plus and minus signs

text: Nicole Oresme's manuscripts from the 14th century show what may be one of the earliest uses of as a sign for plus.


title: Plus and minus signs

text: The symbols (P with overline, , for (more), i.e., plus, and M with overline, , for (less), i.e., minus) appeared for the first time in Luca Pacioli's mathematics compendium, , first printed and published in Venice in 1494.


title: Plus and minus signs

text: The sign is a simplification of the (comparable to the evolution of the ampersand ). The may be derived from a tilde written over when used to indicate subtraction; or it may come from a shorthand version of the letter itself.


title: Plus and minus signs

text: In his 1489 treatise, Johannes Widmann referred to the symbols and as "minus" and "mer" (Modern German ; "more"): They weren't used for addition and subtraction in the treatise, but were used to indicate surplus and deficit; usage in the modern sense is attested in a 1518 book by Henricus Grammateus.


title: Plus and minus signs

text: Robert Recorde, the designer of the equals sign, introduced plus and minus to Britain in 1557 in "The Whetstone of Witte": "There be other 2 signes in often use of which the first is made thus + and betokeneth more: the other is thus made − and betokeneth lesse."


title: Plus and minus signs

text: The plus sign, , is a binary operator that indicates addition, as in . It can also serve as a unary operator that leaves its operand unchanged ( means the same as ). This notation may be used when it is desired to emphasize the positiveness of a number, especially in contrast with the negative numbers ( versus ).


title: Plus and minus signs

text: The plus sign can also indicate many other operations, depending on the mathematical system under consideration. Many algebraic structures, such as vector spaces and matrix rings, have some operation which is called, or is equivalent to, addition. It is though conventional to use the plus sign to only denote commutative operations.


title: Plus and minus signs

text: In many contexts, it does not matter whether the second or the third of these usages is intended: is the same number. When it is important to distinguish them, a raised minus sign is sometimes used for negative constants, as in elementary education, the programming language APL, and some early graphing calculators.


title: Plus and minus signs

text: All three uses can be referred to as "minus" in everyday speech, though the binary operator is sometimes read as "take away". In American English nowadays, −5 (for example) is generally referred to as "negative five" though speakers born before 1950 often refer to it as "minus five". (Temperatures tend to follow the older usage; −5° is generally called "minus five degrees".) Further, a few textbooks in the United States encourage to be read as "the opposite of " or "the additive inverse of "—to avoid giving the impression that is necessarily negative (since itself may already be negative).


title: Plus and minus signs

text: In mathematics and most programming languages, the rules for the order of operations mean that is equal to : Exponentiation binds more strongly than the unary minus, which binds more strongly than multiplication or division. However, in some programming languages (Microsoft Excel in particular), unary operators bind strongest, so in those cases is 25, but is −25.


title: Plus and minus signs

text: Some elementary teachers use raised plus and minus signs before numbers to show they are positive or negative numbers. For example, subtracting −5 from 3 might be read as "positive three take away negative 5", and be shown as


title: Plus and minus signs

text: In grading systems (such as examination marks), the plus sign indicates a grade one level higher and the minus sign a grade lower. For example, ("B minus") is one grade lower than . In some occasions, this is extended to two plus or minus signs (e.g., being two grades higher than ).


title: Plus and minus signs

text: In mathematics the one-sided limit means approaches from the right (i.e., right-sided limit), and means approaches from the left (i.e., left-sided limit). For example, as but as .


title: Plus and minus signs

text: Blood types are often qualified with a plus or minus to indicate the presence or absence of the Rh factor. For example, A+ means type A blood with the Rh factor present, while B− means type B blood with the Rh factor absent.


title: Plus and minus signs

text: In music, augmented chords are symbolized with a plus sign, although this practice is not universal (as there are other methods for spelling those chords). For example, "C+" is read "C augmented chord". Sometimes the plus is written as a superscript.


title: Plus and minus signs

text: As well as the normal mathematical usage, plus and minus signs may be used for a number of other purposes in computing.


title: Plus and minus signs

text: Plus and minus signs are often used in tree view on a computer screen—to show if a folder is collapsed or not.


title: Plus and minus signs

text: In most programming languages, subtraction and negation are indicated with the ASCII hyphen-minus character, . In APL a raised minus sign (Unicode U+00AF) is used to denote a negative number, as in . While in J a negative number is denoted by an underscore, as in .


title: Plus and minus signs

text: In C and some other computer programming languages, two plus signs indicate the increment operator and two minus signs a decrement; the position of the operator before or after the variable indicates whether the new or old value is read from it. For example, if x equals 6, then increments x to 7 but sets y to 6, whereas would set both x and y to 7. By extension, is sometimes used in computing terminology to signify an improvement, as in the name of the language C++.


title: Plus and minus signs

text: In regular expressions, is often used to indicate "1 or more" in a pattern to be matched. For example, means "one or more of the letter x".


title: Plus and minus signs

text: There is no concept of negative zero in mathematics, but in computing −0 may have a separate representation from zero. In the IEEE floating-point standard, 1 / −0 is negative infinity (formula_1) whereas 1 / 0 is positive infinity (formula_2).


title: Plus and minus signs

text: In physics, the use of plus and minus signs for different electrical charges was introduced by Georg Christoph Lichtenberg.


title: Plus and minus signs

text: In chemistry, superscripted plus and minus signs are used to indicate an ion with a positive or negative charge of 1 (e.g., NH). If the charge is greater than 1, a number indicating the charge is written before the sign (as in SO). The minus sign is also used, in place of an en dash, for a single covalent bond between two atoms as in the skeletal formula.


title: Plus and minus signs

text: In the International Phonetic Alphabet, subscripted plus and minus signs are used as diacritics to indicate advanced or retracted articulations of speech sounds.


title: Plus and minus signs

text: The minus sign is also used as tone letter in the orthographies of Dan, Krumen, Karaboro, Mwan, Wan, Yaouré, Wè, Nyabwa and Godié. The Unicode character used for the tone letter (U+02D7) is different from the mathematical minus sign.


title: Plus and minus signs

text: In the algebraic notation used to record games of chess, the plus sign is used to denote a move that puts the opponent into check, while a double plus is sometimes used to denote double check. Combinations of the plus and minus signs are used to evaluate a move (+/−, +/=, =/+, −/+).


title: Plus and minus signs

text: In linguistics, a superscript plus sometimes replaces the asterisk, which denotes unattested linguistic reconstruction.


title: Plus and minus signs

text: A plus sign written at the beginning of an international phone number is the "international prefix symbol" that "serves to remind the subscriber to dial the international prefix which differs from country to country and also serves to identify the number following as the international telephone number."


title: Plus and minus signs

text: The hyphen-minus sign, , is the original ASCII version of the minus sign, which doubles as a hyphen. It is usually shorter in length than the plus sign and often at a different height to the plus-sign's cross bar. It can be used as a substitute for the true minus sign when the character set is limited to ASCII. Most programming languages and other computer readable languages do this, since ASCII is generally available as a subset of most character encodings, while U+2212 is a Unicode feature only. Also several other software programs usable for calculations don't accept the U+2212 minus. For example, pasting <nowiki>=3−2</nowiki> into Excel or <nowiki>3−2=</nowiki> into the Windows calculator won't work.


title: Plus and minus signs

text: As the true minus is not available on most keyboard layouts, typographers sometimes use the very similar en dash, U+2013, to represent the minus sign although it is "not preferred" in mathematical typesetting. Ways of producing the en dash are available on most computers; see .


title: Plus and minus signs

text: There is a commercial minus sign, , which is used in Germany and Scandinavia. The symbol is used to denote subtraction in Scandinavia.


title: Plus and minus signs

text: A Jewish tradition that dates from at least the 19th century is to write "plus" using the symbol . This practice was adopted into Israeli schools and is still commonplace today in elementary schools (including secular schools) but in fewer secondary schools. It is also used occasionally in books by religious authors, but most books for adults use the international symbol . The reason for this practice is that it avoids the writing of a symbol that looks like a Christian cross. Unicode has this symbol at position .


title: Miocene

text: The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene.


title: Miocene

text: As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch.


title: Miocene

text: During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the late Miocene, the connections between the Atlantic and Mediterranean closed, causing the Mediterranean Sea to nearly completely evaporate, in an event called the Messinian salinity crisis. The Strait of Gibraltar opened and the Mediterranean refilled at the Miocene–Pliocene boundary, in an event called the Zanclean flood.


title: Miocene

text: The apes first evolved, arose, and diversified during the early Miocene (Aquitanian and Burdigalian Stages), becoming widespread in the Old World. By the end of this epoch and the start of the following one, the ancestors of humans had split away from the ancestors of the chimpanzees to follow their own evolutionary path during the final Messinian Stage (7.5–5.3 Ma) of the Miocene. As in the Oligocene before it, grasslands continued to expand and forests to dwindle in extent. In the seas of the Miocene, kelp forests made their first appearance and soon became one of Earth's most productive ecosystems.


title: Miocene

text: The plants and animals of the Miocene were recognizably modern. Mammals and birds were well-established. Whales, pinnipeds, and kelp spread.


title: Miocene

text: The Miocene is of particular interest to geologists and palaeoclimatologists as major phases of the geology of the Himalaya occurred during the Miocene, affecting monsoonal patterns in Asia, which were interlinked with glacial periods in the northern hemisphere.


title: Miocene

text: The Miocene faunal stages from youngest to oldest are typically named according to the International Commission on Stratigraphy:


title: Miocene

text: Regionally, other systems are used, based on characteristic land mammals; some of them overlap with the preceding Oligocene and following Pliocene Epochs:


title: Miocene

text: Continents continued to drift toward their present positions. Of the modern geologic features, only the land bridge between South America and North America was absent, although South America was approaching the western subduction zone in the Pacific Ocean, causing both the rise of the Andes and a southward extension of the Meso-American peninsula.


title: Miocene

text: Mountain building took place in western North America, Europe, and East Asia. Both continental and marine Miocene deposits are common worldwide with marine outcrops common near modern shorelines. Well studied continental exposures occur in the North American Great Plains and in Argentina.


title: Miocene

text: The global trend was towards increasing aridity caused primarily by global cooling reducing the ability of the atmosphere to absorb moisture, particularly after 7 to 8 million years ago. Uplift of East Africa in the late Miocene was partly responsible for the shrinking of tropical rain forests in that region, and Australia got drier as it entered a zone of low rainfall in the Late Miocene.


title: Miocene

text: India continued to collide with Asia, creating dramatic new mountain ranges as well as uplifting the Tibetan Plateau, which resulted in the aridification of the Asian interior. At the beginning of the Miocene, the northern margin of the Arabian plate, then part of the African landmass, collided with Eurasia; as a result, the Tethys seaway continued to shrink and then disappeared as Africa collided with Eurasia in the Turkish–Arabian region between 19 and 12 Ma. This severed the connection between the Indian Ocean and the Mediterranean Sea and formed the present land connection between Afro-Arabia and Eurasia. The subsequent uplift of mountains in the western Mediterranean region and a global fall in sea levels combined to cause a temporary drying up of the Mediterranean Sea (known as the Messinian salinity crisis) near the end of the Miocene.


title: Miocene

text: During the Oligocene and Early Miocene, the coast of northern Brazil, Colombia, south-central Peru, central Chile and large swathes of inland Patagonia were subject to a marine transgression. The transgressions in the west coast of South America are thought to be caused by a regional phenomenon while the steadily rising central segment of the Andes represents an exception. While there are numerous registers of Oligo-Miocene transgressions around the world it is doubtful that these correlate.


title: Miocene

text: It is thought that the Oligo-Miocene transgression in Patagonia could have temporarily linked the Pacific and Atlantic Oceans, as inferred from the findings of marine invertebrate fossils of both Atlantic and Pacific affinity in La Cascada Formation. Connection would have occurred through narrow epicontinental seaways that formed channels in a dissected topography.


title: Miocene

text: The Antarctic Plate started to subduct beneath South America 14 million years ago in the Miocene, forming the Chile Triple Junction. At first the Antarctic Plate subducted only in the southernmost tip of Patagonia, meaning that the Chile Triple Junction lay near the Strait of Magellan. As the southern part of Nazca Plate and the Chile Rise became consumed by subduction the more northerly regions of the Antarctic Plate begun to subduct beneath Patagonia so that the Chile Triple Junction advanced to the north over time. The asthenospheric window associated to the triple junction disturbed previous patterns of mantle convection beneath Patagonia inducing an uplift of ca. 1 km that reversed the Oligocene–Miocene transgression.


title: Miocene

text: As the southern Andes rose in the Middle Miocene (14–12 million years ago) the resulting rain shadow originated the Patagonian Desert to the east.


title: Miocene

text: Climates remained moderately warm, although the slow global cooling that eventually led to the Pleistocene glaciations continued.


title: Miocene

text: Although a long-term cooling trend was well underway, there is evidence of a warm period during the Miocene when the global climate rivalled that of the Oligocene. The Miocene warming began 21 million years ago and continued until 14 million years ago, when global temperatures took a sharp drop—the Middle Miocene Climate Transition (MMCT). By 7 to 8 million years ago, temperatures dropped sharply once again, most likely as a result of a decline in atmospheric carbon dioxide and a drop in the amplitude of Earth's obliquity, and the Antarctic ice sheet was already approaching its present-day size and thickness. Greenland may have begun to have large glaciers as early as 7 to 8 million years ago, although the climate for the most part remained warm enough to support forests there well into the Pliocene. At the terminus of the Miocene, global temperatures rose once again as the amplitude of Earth's obliquity increased.


title: Miocene

text: Life during the Miocene Epoch was mostly supported by the two newly formed biomes, kelp forests and grasslands. Grasslands allow for more grazers, such as horses, rhinoceroses, and hippos. Ninety-five percent of modern plants existed by the end of this epoch. Modern bony fish genera were established.


title: Miocene

text: The coevolution of gritty, fibrous, fire-tolerant grasses and long-legged gregarious ungulates with high-crowned teeth, led to a major expansion of grass-grazer ecosystems, with roaming herds of large, swift grazers pursued by predators across broad sweeps of open grasslands, displacing desert, woodland, and browsers.


title: Miocene

text: The higher organic content and water retention of the deeper and richer grassland soils, with long-term burial of carbon in sediments, produced a carbon and water vapor sink. This, combined with higher surface albedo and lower evapotranspiration of grassland, contributed to a cooler, drier climate. C grasses, which are able to assimilate carbon dioxide and water more efficiently than C grasses, expanded to become ecologically significant near the end of the Miocene between 6 and 7 million years ago. The expansion of grasslands and radiations among terrestrial herbivores correlates to fluctuations in CO.


title: Miocene

text: Cycads between 11.5 and 5 million years ago began to rediversify after previous declines in variety due to climatic changes, and thus modern cycads are not a good model for a "living fossil". Eucalyptus fossil leaves occur in the Miocene of New Zealand, where the genus is not native today, but have been introduced from Australia.


title: Miocene

text: Both marine and continental fauna were fairly modern, although marine mammals were less numerous. Only in isolated South America and Australia did widely divergent fauna exist.


title: Miocene

text: In the Early Miocene, several Oligocene groups were still diverse, including nimravids, entelodonts, and three-toed equids. Like in the previous Oligocene Epoch, oreodonts were still diverse, only to disappear in the earliest Pliocene. During the later Miocene mammals were more modern, with easily recognizable canids, bears, red pandas, procyonids, equids, beavers, deer, camelids, and whales, along with now extinct groups like borophagine canids, certain gomphotheres, three-toed horses, and hornless rhinos like "Teleoceras" and "Aphelops". Islands began to form between South and North America in the Late Miocene, allowing ground sloths like "Thinobadistes" to island-hop to North America. The expansion of silica-rich C grasses led to worldwide extinctions of herbivorous species without high-crowned teeth.


title: Miocene

text: Mustelids diversified into their largest forms as terrestrial predators like "Ekorus", "Eomellivora", and "Megalictis" and bunodont otters like "Enhydriodon" and "Sivaonyx" appeared.


title: Miocene

text: Unequivocally recognizable dabbling ducks, plovers, typical owls, cockatoos and crows appear during the Miocene. By the epoch's end, all or almost all modern bird groups are believed to have been present; the few post-Miocene bird fossils which cannot be placed in the evolutionary tree with full confidence are simply too badly preserved, rather than too equivocal in character. Marine birds reached their highest diversity ever in the course of this epoch.


title: Miocene

text: The youngest representatives of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic, are known from the Miocene of Europe, belonging to the genus "Lazarussuchus," which had been the only known surviving genus of the group since the beginning of the Eocene.


title: Miocene

text: The last known representatives of the archaic primitive mammal order Meridiolestida, which dominated South America during the Late Cretaceous, are known from the Miocene of Patagonia, represented by the mole-like "Necrolestes."


title: Miocene

text: The youngest known representatives of metatherians (marsupial relatives) in the Northern Hemisphere landmasses (Asia, North America and Europe) and Africa are known from the Miocene, including the North American herpetotheriid "Herpetotherium", the European herpetotheriid "Amphiperatherium," the peradectids "Siamoperadectes" and "Sinoperadectes" from Asia, and the possible herpetotheriid "Morotodon" from the late Early Miocene of Uganda.


title: Miocene

text: Approximately 100 species of apes lived during this time, ranging throughout Africa, Asia and Europe and varying widely in size, diet, and anatomy. Due to scanty fossil evidence it is unclear which ape or apes contributed to the modern hominid clade, but molecular evidence indicates this ape lived between 18 and 13 million years ago. The first hominins (bipedal apes of the human lineage) appeared in Africa at the very end of the Miocene, including "Sahelanthropus", "Orrorin", and an early form of "Ardipithecus" ("A. kadabba") The chimpanzee–human divergence is thought to have occurred at this time.


title: Miocene

text: The expansion of grasslands in North America also led to an explosive radiation among snakes. Previously, snakes were a minor component of the North American fauna, but during the Miocene, the number of species and their prevalence increased dramatically with the first appearances of vipers and elapids in North America and the significant diversification of Colubridae (including the origin of many modern genera such as "Nerodia", "Lampropeltis", "Pituophis" and "Pantherophis").


title: Miocene

text: In the oceans, brown algae, called kelp, proliferated, supporting new species of sea life, including otters, fish and various invertebrates.


title: Miocene

text: Cetaceans attained their greatest diversity during the Miocene, with over 20 recognized genera of baleen whales in comparison to only six living genera. This diversification correlates with emergence of gigantic macro-predators such as megatoothed sharks and raptorial sperm whales. Prominent examples are "O. megalodon" and "L. melvillei". Other notable large sharks were "O. chubutensis", "Isurus hastalis", and "Hemipristis serra".


title: Miocene

text: Crocodilians also showed signs of diversification during Miocene. The largest form among them was a gigantic caiman "Purussaurus" which inhabited South America. Another gigantic form was a false gharial "Rhamphosuchus", which inhabited modern age India. A strange form, "Mourasuchus" also thrived alongside "Purussaurus". This species developed a specialized filter-feeding mechanism, and it likely preyed upon small fauna despite its gigantic size. The youngest members of Sebecidae, a clade of terrestrial crocodylfomes distantly related to modern crocodilians, are known from the Miocene of South America.


title: Miocene

text: The last Desmostylians thrived during this period before becoming the only extinct marine mammal order.


title: Miocene

text: The pinnipeds, which appeared near the end of the Oligocene, became more aquatic. A prominent genus was "Allodesmus". A ferocious walrus, "Pelagiarctos" may have preyed upon other species of pinnipeds including "Allodesmus".


title: Miocene

text: Furthermore, South American waters witnessed the arrival of "Megapiranha paranensis", which were considerably larger than modern age piranhas.


title: Miocene

text: New Zealand's Miocene fossil record is particularly rich. Marine deposits showcase a variety of cetaceans and penguins, illustrating the evolution of both groups into modern representatives. The early Miocene Saint Bathans Fauna is the only Cenozoic terrestrial fossil record of the landmass, showcasing a wide variety of not only bird species, including early representatives of clades such as moas, kiwis and adzebills, but also a diverse herpetofauna of sphenodontians, crocodiles and turtle as well as a rich terrestrial mammal fauna composed of various species of bats and the enigmatic Saint Bathans Mammal.


title: Miocene

text: There is evidence from oxygen isotopes at Deep Sea Drilling Program sites that ice began to build up in Antarctica about 36 Ma during the Eocene. Further marked decreases in temperature during the Middle Miocene at 15 Ma probably reflect increased ice growth in Antarctica. It can therefore be assumed that East Antarctica had some glaciers during the early to mid Miocene (23–15 Ma). Oceans cooled partly due to the formation of the Antarctic Circumpolar Current, and about 15 million years ago the ice cap in the southern hemisphere started to grow to its present form. The Greenland ice cap developed later, in the Middle Pliocene time, about 3 million years ago.


title: Miocene

text: The "Middle Miocene disruption" refers to a wave of extinctions of terrestrial and aquatic life forms that occurred following the Miocene Climatic Optimum (18 to 16 Ma), around 14.8 to 14.5 million years ago, during the Langhian Stage of the mid-Miocene. A major and permanent cooling step occurred between 14.8 and 14.1 Ma, associated with increased production of cold Antarctic deep waters and a major growth of the East Antarctic ice sheet. A Middle Miocene δO increase, that is, a relative increase in the heavier isotope of oxygen, has been noted in the Pacific, the Southern Ocean and the South Atlantic.


title: Miocene

text: A large impact event occurred either during the Miocene (23 Ma – 5.3 Ma) or the Pliocene (5.3 Ma – 2.6 Ma). The event formed the Karakul crater (52 km diameter), in Tajikistan which is estimated to have an age of less than 23 Ma or less than 5 Ma.


title: Oil refinery

text: An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, liquefied petroleum gas and petroleum naphtha. Petrochemicals feedstock like ethylene and propylene can also be produced directly by cracking crude oil without the need of using refined products of crude oil such as naphtha. The crude oil feedstock has typically been processed by an oil production plant. There is usually an oil depot at or near an oil refinery for the storage of incoming crude oil feedstock as well as bulk liquid products. In 2020, the total capacity of global refineries for crude oil was about 101.2 million barrels per day.


title: Oil refinery

text: Oil refineries are typically large, sprawling industrial complexes with extensive piping running throughout, carrying streams of fluids between large chemical processing units, such as distillation columns. In many ways, oil refineries use much of the technology and can be thought of, as types of chemical plants. Since December 2008, the world’s largest oil refinery has been the Jamnagar Refinery owned by Reliance Industries, located in Gujarat, India, with a processing capacity of . Some modern petroleum refineries process as much as 800,000 to 900,000 barrels (120,000 to 143,000 cubic meters) of crude oil per day.


title: Oil refinery

text: The Chinese were among the first civilizations to refine oil. As early as the first century, the Chinese were refining crude oil for use as an energy source. Between 512 and 518, in the late Northern Wei Dynasty, the Chinese geographer, writer and politician Li Daoyuan introduced the process of refining oil into various lubricants in his famous work "Commentary on the Water Classic".


title: Oil refinery

text: Crude oil was often distilled by Arab chemists, with clear descriptions given in Arabic handbooks such as those of Muhammad ibn Zakarīya Rāzi (). The streets of Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region. In the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan. These fields were described by the Arab geographer Abu al-Hasan 'Alī al-Mas'ūdī in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads. Arab and Persian chemists also distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century.


title: Oil refinery

text: In the Northern Song Dynasty (960–1127), a workshop called the "Fierce Oil Workshop", was established in the city of Kaifeng to produce refined oil for the Song military as a weapon. The troops would then fill iron cans with refined oil and throw them toward the enemy troops, causing a fire – effectively the world's first "fire bomb". The workshop was one of the world's earliest oil refining factories where thousands of people worked to produce Chinese oil-powered weaponry.


title: Oil refinery

text: Prior to the nineteenth century, petroleum was known and utilized in various fashions in Babylon, Egypt, China, Philippines, Rome and Azerbaijan. However, the modern history of the petroleum industry is said to have begun in 1846 when Abraham Gessner of Nova Scotia, Canada devised a process to produce kerosene from coal. Shortly thereafter, in 1854, Ignacy Łukasiewicz began producing kerosene from hand-dug oil wells near the town of Krosno, Poland.


title: Oil refinery

text: The world's first industrial petroleum refinery was built in Ploiești, Romania, in 1856 using the abundant oil available in Romania.


title: Oil refinery

text: In North America, the first oil well was drilled in 1858 by James Miller Williams in Oil Springs, Ontario, Canada. In the United States, the petroleum industry began in 1859 when Edwin Drake found oil near Titusville, Pennsylvania. The industry grew slowly in the 1800s, primarily producing kerosene for oil lamps. In the early twentieth century, the introduction of the internal combustion engine and its use in automobiles created a market for gasoline that was the impetus for fairly rapid growth of the petroleum industry. The early finds of petroleum like those in Ontario and Pennsylvania were soon outstripped by large oil "booms" in Oklahoma, Texas and California.


title: Oil refinery

text: Samuel Kier established America's first oil refinery in Pittsburgh on Seventh Avenue near Grant Street, in 1853. Polish pharmacist and inventor Ignacy Łukasiewicz established an oil refinery in Jasło, then part of the Austro-Hungarian Empire (now in Poland) in 1854. The first large refinery opened at Ploiești, Romania, in 1856–1857. After being taken over by Nazi Germany, the Ploiești refineries were bombed in Operation Tidal Wave by the Allies during the Oil Campaign of World War II. Another close contender for the title of hosting the world's oldest oil refinery is Salzbergen in Lower Saxony, Germany. Salzbergen's refinery was opened in 1860.


title: Oil refinery

text: At one point, the refinery in Ras Tanura, Saudi Arabia owned by Saudi Aramco was claimed to be the largest oil refinery in the world. For most of the 20th century, the largest refinery was the Abadan Refinery in Iran. This refinery suffered extensive damage during the Iran–Iraq War. Since 25 December 2008, the world's largest refinery complex is the Jamnagar Refinery Complex, consisting of two refineries side by side operated by Reliance Industries Limited in Jamnagar, India with a combined production capacity of . PDVSA's Paraguaná Refinery Complex in Paraguaná Peninsula, Venezuela, with a capacity of and SK Energy's Ulsan in South Korea with are the second and third largest, respectively.


title: Oil refinery

text: Prior to World War II in the early 1940s, most petroleum refineries in the United States consisted simply of crude oil distillation units (often referred to as atmospheric crude oil distillation units). Some refineries also had vacuum distillation units as well as thermal cracking units such as visbreakers (viscosity breakers, units to lower the viscosity of the oil). All of the many other refining processes discussed below were developed during the war or within a few years after the war. They became commercially available within 5 to 10 years after the war ended and the worldwide petroleum industry experienced very rapid growth. The driving force for that growth in technology and in the number and size of refineries worldwide was the growing demand for automotive gasoline and aircraft fuel.


title: Oil refinery

text: In the United States, for various complex economic and political reasons, the construction of new refineries came to a virtual stop in about the 1980s. However, many of the existing refineries in the United States have revamped many of their units and/or constructed add-on units in order to: increase their crude oil processing capacity, increase the octane rating of their product gasoline, lower the sulfur content of their diesel fuel and home heating fuels to comply with environmental regulations and comply with environmental air pollution and water pollution requirements.


title: Oil refinery

text: The size of the oil refining market in 2017 was valued at over US$6 trillion in 2017 and is set to witness a consumption of over 100 million barrels per day (MBPD) by 2024. The oil refining market will witness an appreciable growth because of rapid industrialization and economic transformation. Changing demographics, growing population, and improvement in living standards across developing nations are some of the factors positively influencing the industry landscape.


title: Oil refinery

text: In the 19th century, refineries in the U.S. processed crude oil primarily to recover the kerosene. There was no market for the more volatile fraction, including gasoline, which was considered waste and was often dumped directly into the nearest river. The invention of the automobile shifted the demand to gasoline and diesel, which remain the primary refined products today.


title: Oil refinery

text: Today, national and state legislation require refineries to meet stringent air and water cleanliness standards. In fact, oil companies in the U.S. perceive obtaining a permit to build a modern refinery to be so difficult and costly that no new refineries were built (though many have been expanded) in the U.S. from 1976 until 2014 when the small Dakota Prairie Refinery in North Dakota began operation. More than half the refineries that existed in 1981 are now closed due to low utilization rates and accelerating mergers. As a result of these closures total US refinery capacity fell between 1981 and 1995, though the operating capacity stayed fairly constant in that time period at around . Increases in facility size and improvements in efficiencies have offset much of the lost physical capacity of the industry. In 1982 (the earliest data provided), the United States operated 301 refineries with a combined capacity of of crude oil each calendar day. In 2010, there were 149 operable U.S. refineries with a combined capacity of per calendar day. By 2014 the number of refinery had reduced to 140 but the total capacity increased to per calendar day. Indeed, in order to reduce operating costs and depreciation, refining is operated in fewer sites but of bigger capacity.


title: Oil refinery

text: In 2009 through 2010, as revenue streams in the oil business dried up and profitability of oil refineries fell due to lower demand for product and high reserves of supply preceding the economic recession, oil companies began to close or sell the less profitable refineries.


title: Oil refinery

text: Raw or unprocessed crude oil is not generally useful in industrial applications, although "light, sweet" (low viscosity, low sulfur) crude oil has been used directly as a burner fuel to produce steam for the propulsion of seagoing vessels. The lighter elements, however, form explosive vapors in the fuel tanks and are therefore hazardous, especially in warships. Instead, the hundreds of different hydrocarbon molecules in crude oil are separated in a refinery into components that can be used as fuels, lubricants, and feedstocks in petrochemical processes that manufacture such products as plastics, detergents, solvents, elastomers, and fibers such as nylon and polyesters.


title: Oil refinery

text: Petroleum fossil fuels are burned in internal combustion engines to provide power for ships, automobiles, aircraft engines, lawn mowers, dirt bikes, and other machines. Different boiling points allow the hydrocarbons to be separated by distillation. Since the lighter liquid products are in great demand for use in internal combustion engines, a modern refinery will convert heavy hydrocarbons and lighter gaseous elements into these higher-value products.


title: Oil refinery

text: Oil can be used in a variety of ways because it contains hydrocarbons of varying molecular masses, forms and lengths such as paraffins, aromatics, naphthenes (or cycloalkanes), alkenes, dienes, and alkynes. While the molecules in crude oil include different atoms such as sulfur and nitrogen, the hydrocarbons are the most common form of molecules, which are molecules of varying lengths and complexity made of hydrogen and carbon atoms, and a small number of oxygen atoms. The differences in the structure of these molecules account for their varying physical and chemical properties, and it is this variety that makes crude oil useful in a broad range of several applications.


title: Oil refinery

text: Once separated and purified of any contaminants and impurities, the fuel or lubricant can be sold without further processing. Smaller molecules such as isobutane and propylene or butylenes can be recombined to meet specific octane requirements by processes such as alkylation, or more commonly, dimerization. The octane grade of gasoline can also be improved by catalytic reforming, which involves removing hydrogen from hydrocarbons producing compounds with higher octane ratings such as aromatics. Intermediate products such as gasoils can even be reprocessed to break a heavy, long-chained oil into a lighter short-chained one, by various forms of cracking such as fluid catalytic cracking, thermal cracking, and hydrocracking. The final step in gasoline production is the blending of fuels with different octane ratings, vapor pressures, and other properties to meet product specifications. Another method for reprocessing and upgrading these intermediate products (residual oils) uses a devolatilization process to separate usable oil from the waste asphaltene material.


title: Oil refinery

text: Oil refineries are large-scale plants, processing about a hundred thousand to several hundred thousand barrels of crude oil a day. Because of the high capacity, many of the units operate continuously, as opposed to processing in batches, at steady state or nearly steady state for months to years. The high capacity also makes process optimization and advanced process control very desirable.


title: Oil refinery

text: Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. The majority of petroleum is converted to petroleum products, which includes several classes of fuels.


title: Oil refinery

text: Oil refineries also produce various intermediate products such as hydrogen, light hydrocarbons, reformate and pyrolysis gasoline. These are not usually transported but instead are blended or processed further on-site. Chemical plants are thus often adjacent to oil refineries or a number of further chemical processes are integrated into it. For example, light hydrocarbons are steam-cracked in an ethylene plant, and the produced ethylene is polymerized to produce polyethene.


title: Oil refinery

text: To ensure both proper separation and environmental protection, a very low sulfur content is necessary in all but the heaviest products. The crude sulfur contaminant is transformed to hydrogen sulfide via catalytic hydrodesulfurization and removed from the product stream via amine gas treating. Using the Claus process, hydrogen sulfide is afterward transformed to elementary sulfur to be sold to the chemical industry. The rather large heat energy freed by this process is directly used in the other parts of the refinery. Often an electrical power plant is combined into the whole refinery process to take up the excess heat.


title: Oil refinery

text: According to the composition of the crude oil and depending on the demands of the market, refineries can produce different shares of petroleum products. The largest share of oil products is used as "energy carriers", i.e. various grades of fuel oil and gasoline. These fuels include or can be blended to give gasoline, jet fuel, diesel fuel, heating oil, and heavier fuel oils. Heavier (less volatile) fractions can also be used to produce asphalt, tar, paraffin wax, lubricating and other heavy oils. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials. Since petroleum often contains a few percent sulfur-containing molecules, elemental sulfur is also often produced as a petroleum product. Carbon, in the form of petroleum coke, and hydrogen may also be produced as petroleum products. The hydrogen produced is often used as an intermediate product for other oil refinery processes such as hydrocracking and hydrodesulfurization.


title: Oil refinery

text: Petroleum products are usually grouped into four categories: light distillates (LPG, gasoline, naphtha), middle distillates (kerosene, jet fuel, diesel), heavy distillates, and residuum (heavy fuel oil, lubricating oils, wax, asphalt). These require blending various feedstocks, mixing appropriate additives, providing short-term storage, and preparation for bulk loading to trucks, barges, product ships, and railcars. This classification is based on the way crude oil is distilled and separated into fractions.


title: Oil refinery

text: Over 6,000 items are made from petroleum waste by-products, including fertilizer, floor coverings, perfume, insecticide, petroleum jelly, soap, vitamin capsules.


title: Oil refinery

text: The image below is a schematic flow diagram of a typical oil refinery that depicts the various unit processes and the flow of intermediate product streams that occurs between the inlet crude oil feedstock and the final end products. The diagram depicts only one of the literally hundreds of different oil refinery configurations. The diagram also does not include any of the usual refinery facilities providing utilities such as steam, cooling water, and electric power as well as storage tanks for crude oil feedstock and for intermediate products and end products.


title: Oil refinery

text: There are many process configurations other than that depicted above. For example, the vacuum distillation unit may also produce fractions that can be refined into end products such as spindle oil used in the textile industry, light machine oil, motor oil, and various waxes.


title: Oil refinery

text: The crude oil distillation unit (CDU) is the first processing unit in virtually all petroleum refineries. The CDU distills the incoming crude oil into various fractions of different boiling ranges, each of which is then processed further in the other refinery processing units. The CDU is often referred to as the "atmospheric distillation unit" because it operates at slightly above atmospheric pressure.


title: Oil refinery

text: Below is a schematic flow diagram of a typical crude oil distillation unit. The incoming crude oil is preheated by exchanging heat with some of the hot, distilled fractions and other streams. It is then desalted to remove inorganic salts (primarily sodium chloride).


title: Oil refinery

text: Following the desalter, the crude oil is further heated by exchanging heat with some of the hot, distilled fractions and other streams. It is then heated in a fuel-fired furnace (fired heater) to a temperature of about 398 °C and routed into the bottom of the distillation unit.


title: Oil refinery

text: The cooling and condensing of the distillation tower overhead is provided partially by exchanging heat with the incoming crude oil and partially by either an air-cooled or water-cooled condenser. Additional heat is removed from the distillation column by a pumparound system as shown in the diagram below.


title: Oil refinery

text: As shown in the flow diagram, the overhead distillate fraction from the distillation column is naphtha. The fractions removed from the side of the distillation column at various points between the column top and bottom are called "sidecuts". Each of the sidecuts (i.e., the kerosene, light gas oil, and heavy gas oil) is cooled by exchanging heat with the incoming crude oil. All of the fractions (i.e., the overhead naphtha, the sidecuts, and the bottom residue) are sent to intermediate storage tanks before being processed further.


title: Oil refinery

text: A party searching for a site to construct a refinery or a chemical plant needs to consider the following issues:


title: Oil refinery

text: Refineries that use a large amount of steam and cooling water need to have an abundant source of water. Oil refineries, therefore, are often located nearby navigable rivers or on a seashore, nearby a port. Such location also gives access to transportation by river or by sea. The advantages of transporting crude oil by pipeline are evident, and oil companies often transport a large volume of fuel to distribution terminals by pipeline. A pipeline may not be practical for products with small output, and railcars, road tankers, and barges are used.


title: Oil refinery

text: Petrochemical plants and solvent manufacturing (fine fractionating) plants need spaces for further processing of a large volume of refinery products, or to mix chemical additives with a product at source rather than at blending terminals.


title: Oil refinery

text: The refining process releases a number of different chemicals into the atmosphere (see AP 42 Compilation of Air Pollutant Emission Factors) and a notable odor normally accompanies the presence of a refinery. Aside from air pollution impacts there are also wastewater concerns, risks of industrial accidents such as fire and explosion, and noise health effects due to industrial noise.


title: Oil refinery

text: Many governments worldwide have mandated restrictions on contaminants that refineries release, and most refineries have installed the equipment needed to comply with the requirements of the pertinent environmental protection regulatory agencies. In the United States, there is strong pressure to prevent the development of new refineries, and no major refinery has been built in the country since Marathon's Garyville, Louisiana facility in 1976. However, many existing refineries have been expanded during that time. Environmental restrictions and pressure to prevent the construction of new refineries may have also contributed to rising fuel prices in the United States. Additionally, many refineries (more than 100 since the 1980s) have closed due to obsolescence and/or merger activity within the industry itself.


title: Oil refinery

text: Environmental and safety concerns mean that oil refineries are sometimes located some distance away from major urban areas. Nevertheless, there are many instances where refinery operations are close to populated areas and pose health risks. In California's Contra Costa County and Solano County, a shoreline necklace of refineries, built in the early 20th century before this area was populated, and associated chemical plants are adjacent to urban areas in Richmond, Martinez, Pacheco, Concord, Pittsburg, Vallejo and Benicia, with occasional accidental events that require "shelter in place" orders to the adjacent populations. A number of refineries are located in Sherwood Park, Alberta, directly adjacent to the City of Edmonton, which has a population of over 1,000,000 residents.


title: Oil refinery

text: NIOSH criteria for occupational exposure to refined petroleum solvents have been available since 1977.


title: Oil refinery

text: Modern petroleum refining involves a complicated system of interrelated chemical reactions that produce a wide variety of petroleum-based products. Many of these reactions require precise temperature and pressure parameters.  The equipment and monitoring required to ensure the proper progression of these processes is complex, and has evolved through the advancement of the scientific field of petroleum engineering.


title: Oil refinery

text: The wide array of high pressure and/or high temperature reactions, along with the necessary chemical additives or extracted contaminants, produces an astonishing number of potential health hazards to the oil refinery worker.  Through the advancement of technical chemical and petroleum engineering, the vast majority of these processes are automated and enclosed, thus greatly reducing the potential health impact to workers.  However, depending on the specific process in which a worker is engaged, as well as the particular method employed by the refinery in which he/she works, significant health hazards remain.


title: Oil refinery

text: Although occupational injuries in the United States were not routinely tracked and reported at the time, reports of the health impacts of working in an oil refinery can be found as early as the 1800s. For instance, an explosion in a Chicago refinery killed 20 workers in 1890. Since then, numerous fires, explosions, and other significant events have from time to time drawn the public's attention to the health of oil refinery workers. Such events continue in the 21st century, with explosions reported in refineries in Wisconsin and Germany in 2018.


title: Oil refinery

text: Given the highly automated and technically advanced nature of modern petroleum refineries, nearly all processes are contained within engineering controls and represent a substantially decreased risk of exposure to workers compared to earlier times. However, certain situations or work tasks may subvert these safety mechanisms, and expose workers to a number of chemical (see table above) or physical (described below) hazards. Examples of these scenarios include:


title: Oil refinery

text: Interestingly, even though petroleum refineries utilize and produce chemicals that are known carcinogens, the literature on cancer rates among refinery workers is mixed. For example, benzene has been shown to have a relationship with leukemia, however studies examining benzene exposure and resultant leukemia specifically in the context of oil refinery workers have come to opposing conclusions. Asbestos-related mesothelioma is another particular cancer-carcinogen relationship that has been investigated in the context of oil refinery workers. To date, this work has shown a marginally significant link to refinery employment and mesothelioma. Notably, a meta-analysis which included data on more than 350,000 refinery workers failed to find any statistically significant excess rates of cancer mortality, except for a marginally significant increase in melanoma deaths. An additional US-based study included a follow-up period of 50 years among over 17,000 workers. This study concluded that there was no excess mortality among this cohort as a result of employment.


title: Oil refinery

text: BTX stands for benzene, toluene, xylene. This is a group of common volatile organic compounds (VOCs) that are found in the oil refinery environment, and serve as a paradigm for more in depth discussion of occupational exposure limits, chemical exposure and surveillance among refinery workers.


title: Oil refinery

text: The most important route of exposure for BTX chemicals is inhalation due to the low boiling point of these chemicals. The majority of the gaseous production of BTX occurs during tank cleaning and fuel transfer, which causes offgassing of these chemicals into the air. Exposure can also occur through ingestion via contaminated water, but this is unlikely in an occupational setting. Dermal exposure and absorption is also possible, but is again less likely in an occupational setting where appropriate personal protective equipment is in place.


title: Oil refinery

text: In the United States, the Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety and Health (NIOSH), and American Conference of Governmental Industrial Hygienists (ACGIH) have all established occupational exposure limits (OELs) for many of the chemicals above that workers may be exposed to in petroleum refineries.


title: Oil refinery

text: Benzene, in particular, has multiple biomarkers that can be measured to determine exposure. Benzene itself can be measured in the breath, blood, and urine, and metabolites such as phenol, "t","t"-muconic acid ("t","t"MA) and S-phenylmercapturic acid ("s"PMA) can be measured in urine. In addition to monitoring the exposure levels via these biomarkers, employers are required by OSHA to perform regular blood tests on workers to test for early signs of some of the feared hematologic outcomes, of which the most widely recognized is leukemia. Required testing includes complete blood count with cell differentials and peripheral blood smear "on a regular basis". The utility of these tests is supported by formal scientific studies.


title: Oil refinery

text: Workers are at risk of physical injuries due to a large number of high-powered machines in the relatively close proximity of the oil refinery. The high pressure required for many of the chemical reactions also presents the possibility of localized system failures resulting in blunt or penetrating trauma from exploding system components.


title: Oil refinery

text: Heat is also a hazard. The temperature required for the proper progression of certain reactions in the refining process can reach . As with chemicals, the operating system is designed to safely contain this hazard without injury to the worker. However, in system failures, this is a potent threat to workers’ health. Concerns include both direct injury through a heat illness or injury, as well as the potential for devastating burns should the worker come in contact with super-heated reagents/equipment.


title: Oil refinery

text: Noise is another hazard. Refineries can be very loud environments, and have previously been shown to be associated with hearing loss among workers. The interior environment of an oil refinery can reach levels in excess of 90 dB. In the United States, an average of 90 dB is the permissible exposure limit (PEL) for an 8-hour work-day. Noise exposures that average greater than 85 dB over an 8-hour require a hearing conservation program to regularly evaluate workers' hearing and to promote its protection.  Regular evaluation of workers’ auditory capacity and faithful use of properly vetted hearing protection are essential parts of such programs.


title: Oil refinery

text: While not specific to the industry, oil refinery workers may also be at risk for hazards such as vehicle-related accidents, machinery-associated injuries, work in a confined space, explosions/fires, ergonomic hazards, shift-work related sleep disorders, and falls.


title: Oil refinery

text: The theory of hierarchy of controls can be applied to petroleum refineries and their efforts to ensure worker safety.


title: Oil refinery

text: Elimination and substitution are unlikely in petroleum refineries, as many of the raw materials, waste products, and finished products are hazardous in one form or another (e.g. flammable, carcinogenic).


title: Oil refinery

text: Examples of engineering controls include a fire detection/extinguishing system, pressure/chemical sensors to detect/predict loss of structural integrity, and adequate maintenance of piping to prevent hydrocarbon-induced corrosion (leading to structural failure). Other examples employed in petroleum refineries include the post-construction protection of steel components with vermiculite to improve heat/fire resistance. Compartmentalization can help to prevent a fire or other systems failure from spreading to affect other areas of the structure, and may help prevent dangerous reactions by keeping different chemicals separate from one another until they can be safely combined in the proper environment.


title: Oil refinery

text: Administrative controls include careful planning and oversight of the refinery cleaning, maintenance, and turnaround processes. These occur when many of the engineering controls are shut down or suppressed and may be especially dangerous to workers. Detailed coordination is necessary to ensure that maintenance of one part of the facility will not cause dangerous exposures to those performing the maintenance, or to workers in other areas of the plant. Due to the highly flammable nature of many of the involved chemicals, smoking areas are tightly controlled and carefully placed.


title: Oil refinery

text: Personal protective equipment (PPE) may be necessary depending on the specific chemical being processed or produced. Particular care is needed during sampling of the partially-completed product, tank cleaning, and other high-risk tasks as mentioned above. Such activities may require the use of impervious outerwear, acid hood, disposable coveralls, etc. More generally, all personnel in operating areas should use appropriate hearing and vision protection, avoid clothes made of flammable material (nylon, Dacron, acrylic, or blends), and full-length pants and sleeves.


title: Oil refinery

text: Worker health and safety in oil refineries is closely monitored at a national level by both the Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH). In addition to federal monitoring, California's CalOSHA has been particularly active in protecting worker health in the industry, and adopted a policy in 2017 that requires petroleum refineries to perform a "Hierarchy of Hazard Controls Analysis" (see above "Hazard controls" section) for each process safety hazard. Safety regulations have resulted in a below-average injury rate for refining industry workers. In a 2018 report by the US Bureau of Labor Statistics, they indicate that petroleum refinery workers have a significantly lower rate of occupational injury (0.4 OSHA-recordable cases per 100 full-time workers) than all industries (3.1 cases), oil and gas extraction (0.8 cases), and petroleum manufacturing in general (1.3 cases).


title: Oil refinery

text: Below is a list of the most common regulations referenced in petroleum refinery safety citations issued by OSHA:


title: Oil refinery

text: Corrosion of metallic components is a major factor of inefficiency in the refining process. Because it leads to equipment failure, it is a primary driver for the refinery maintenance schedule. Corrosion-related direct costs in the U.S. petroleum industry as of 1996 were estimated at US$3.7 billion.


title: Oil refinery

text: Corrosion occurs in various forms in the refining process, such as pitting corrosion from water droplets, embrittlement from hydrogen, and stress corrosion cracking from sulfide attack.</ref> From a materials standpoint, carbon steel is used for upwards of 80 percent of refinery components, which is beneficial due to its low cost. Carbon steel is resistant to the most common forms of corrosion, particularly from hydrocarbon impurities at temperatures below 205 °C, but other corrosive chemicals and environments prevent its use everywhere. Common replacement materials are low alloy steels containing chromium and molybdenum, with stainless steels containing more chromium dealing with more corrosive environments. More expensive materials commonly used are nickel, titanium, and copper alloys. These are primarily saved for the most problematic areas where extremely high temperatures and/or very corrosive chemicals are present.


title: Oil refinery

text: Corrosion is fought by a complex system of monitoring, preventative repairs, and careful use of materials. Monitoring methods include both offline checks taken during maintenance and online monitoring. Offline checks measure corrosion after it has occurred, telling the engineer when equipment must be replaced based on the historical information they have collected. This is referred to as preventative management.


title: Oil refinery

text: Online systems are a more modern development and are revolutionizing the way corrosion is approached. There are several types of online corrosion monitoring technologies such as linear polarization resistance, electrochemical noise and electrical resistance. Online monitoring has generally had slow reporting rates in the past (minutes or hours) and been limited by process conditions and sources of error but newer technologies can report rates up to twice per minute with much higher accuracy (referred to as real-time monitoring). This allows process engineers to treat corrosion as another process variable that can be optimized in the system. Immediate responses to process changes allow the control of corrosion mechanisms, so they can be minimized while also maximizing production output. In an ideal situation having on-line corrosion information that is accurate and real-time will allow conditions that cause high corrosion rates to be identified and reduced. This is known as predictive management.