96-528: The MG 3 is a German general-purpose machine gun chambered for the 7.62×51mm NATO cartridge. The weapon's design is derived from the World War II era MG 42 that fired the 7.92×57mm Mauser round. The MG 3 was standardized in the late 1950s and adopted into service with the newly formed Bundeswehr , where it continues to serve to this day as a squad support weapon and a vehicle-mounted machine gun. The weapon and its derivatives have also been acquired by
192-424: A 100-round DM1 belt or a 120-round DM60/M13 belt. The German military tends to use non-disintegrating DM1 belts for general use and disintegrating DM60/M13 belts in vehicle or aircraft fixed MG3 mountings that allow for collecting the ejected link pieces for reuse. The open-type iron sighting line has a relatively short 430 millimeters (16.9 in) radius and consists of a "∧-type" height adjustable front sight on
288-551: A 13-year timeframe, and that the EPA did not provide adequate evidence for the safety of alternative products. Until the mid-1980s, small amounts of white asbestos were used in the manufacture of Artex , a decorative stipple finish, however, some of the lesser-known suppliers of Artex-type materials were still adding white asbestos until 1999. Before the ban, asbestos was widely used in the construction industry in thousands of materials. Some are judged to be more dangerous than others due to
384-504: A Christian bishop living in 4th-century Egypt, references asbestos in one of his writings. Around the year 318, he wrote as follows: The natural property of fire is to burn. Suppose, then, that there was a substance such as the Indian asbestos is said to be, which had no fear of being burnt, but rather displayed the impotence of the fire by proving itself unburnable. If anyone doubted the truth of this, all he need do would be to wrap himself up in
480-607: A buffered Feldlafette ("field tripod") that also features storage containers for accessories like the Zielfernrohr 4 × 24 periscope-style telescopic sight. The direct fire only Zielfernrohr 4 × 24 sight like the MG 3 is mounted on the Feldlafette and is graduated from 0 to 1,600 meters (0 to 1,750 yd) in 100 meters (109 yd) increments. The Zielfernrohr 4 × 24 reticle can be illuminated by an external unit. It can also be used with
576-744: A certified asbestos-testing laboratory found the tremolite form of amphibole asbestos used to be found in three out of eight popular brands of children's crayons that were made partly from talc: Crayola , Prang, and RoseArt. In Crayola crayons, the tests found asbestos levels around 0.05% in Carnation Pink and 2.86% in Orchid ; in Prang crayons, the range was from 0.3% in Periwinkle to 0.54% in Yellow ; in Rose Art crayons, it
672-618: A folding post and a leaf rear sight with an open V-notch sliding on a ramp, graduated from 200 to 1,200 meters (219 to 1,312 yd) in 100 meters (109 yd) increments. A flip-up anti-aircraft sight is attached to the receiver top just in front of the normal rear sight element. As an iron sighting line alternative, the Danish military uses a 3.4×28 optical sight mounted on top of the receiver which can be set from 300 to 800 meters (328 to 875 yd) in 100 meters (109 yd) increments on their MG 3 (designated as M/62) and later M/60E6 . What sets
768-613: A large number of early deaths and lung problems in asbestos-mining towns. The first such study was conducted by Murray at the Charing Cross Hospital , London , in 1900, in which a postmortem investigation discovered asbestos traces in the lungs of a young man who had died from pulmonary fibrosis after having worked for 14 years in an asbestos textile factory. Adelaide Anderson , the Inspector of Factories in Britain, included asbestos in
864-609: A list of harmful industrial substances in 1902. Similar investigations were conducted in France in 1906 and Italy in 1908. The first diagnosis of asbestosis was made in the UK in 1924. Nellie Kershaw was employed at Turner Brothers Asbestos in Rochdale , Greater Manchester , England , from 1917, spinning raw asbestos fibre into yarn. Her death in 1924 led to a formal inquest. Pathologist William Edmund Cooke testified that his examination of
960-550: A materials analyst whose testimony on behalf of the asbestos industry has been accepted in lawsuits over 250 times, found its crayons tested negative for asbestos. In spite of that, in June 2000 Binney & Smith, the maker of Crayola, and the other makers agreed to stop using talc in their products, and changed their product formulations in the United States. The mining company R T Vanderbilt Co of Gouverneur, New York , which supplied
1056-406: A metal lip that is arrested in the rim of the cartridges to correctly position and fix the cartridges in place. The feeding system is based on the direct push-through of the cartridge out of the belt link into the gun's chamber. Feed is performed in two steps by a pawl-type feeding mechanism that continues to move the belt during both the rearward and forward cycles of the reciprocating bolt, producing
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#17330850446481152-459: A potential health hazard and is no longer used at all. Amphiboles including amosite (brown asbestos) and crocidolite (blue asbestos) were formerly used in many products until the early 1980s. Tremolite asbestos constituted a contaminant of many if not all naturally occurring chrysotile deposits. The use of all types of asbestos in the amphibole group was banned in much of the Western world by
1248-494: A rate of 850 rounds per minute , with lethality at ranges of more than 1,000 meters . The main feature of the MG 34 is that simply by changing its mount, sights and feed mechanism, the operator could radically transform its function: on its standard bipod it was a light machine gun ideal for infantry assaults; on a tripod it could serve as a sustained-fire medium machine gun ; mounting on aircraft or vehicles turned it into an air defence weapon, and it also served as
1344-511: A reasonable doubt, the primary cause of the fibrosis of the lungs and therefore of death." As a result of Cooke's paper, Parliament commissioned an inquiry into the effects of asbestos dust by E. R. A. Merewether, Medical Inspector of Factories, and C. W. Price , a factory inspector and pioneer of dust monitoring and control. Their subsequent report, Occurrence of Pulmonary Fibrosis & Other Pulmonary Affections in Asbestos Workers ,
1440-401: A roller locked bolt mechanism that consists of the bolt head, a pair of rollers, the striker sleeve, bolt body and return spring. The bolt is locked securely by a wedge-shaped striker sleeve, which forces two cylindrical rollers contained in the bolt head outward, and into corresponding recesses in the extension of the breech of the barrel. On firing, both the barrel and barrel extension recoil to
1536-466: A slower 800–950 rounds per minute cyclic rate of fire. Those bolts also are used along with different return springs . The MG 3 feeds from the left side through a feed block using metal, 50-round continuous-link Patronengurt DM1 ammunition belts (which can be combined by cartridge) or disintegrating-link M13 or DM6 belts. In the light machine gun role, the MG 3 is deployed with a 100-round (or 120-round in case of disintegrating belts) belt fitted inside
1632-423: A smooth belt flow. For field use there are several ammunition containers available. The Gurttrommel (belt drum) contains a 50-round DM1 or DM60 belt. The Gurttrommel is not a true magazine but holds a curled 50-round belt preventing it from snagging, twisting and getting stuck during mobile assaults. The steel DM2 ammunition box contains a 250-round DM1 belt and the smaller plastic DM40004 ammunition box contains
1728-424: A synthetic ammunition drum developed by Heckler & Koch that is latched on to the left side of the receiver. The rear wall of the drum is transparent and serves as a visual indicator for the amount of ammunition available. The feed system operates through a feed arm that is housed in the feed cover. Two feed pawls are linked to the front end of the arm by an intermediate link and move in opposite directions, moving
1824-399: Is advantageous for use against targets typically exposed to fire for a limited time span, like aircraft or targets minimizing their exposure by quickly moving from cover to cover. It was nicknamed " Hitler 's buzzsaw " by Allied troops, and alongside the MG 34 it inflicted heavy casualties on Allied soldiers on all European and North African fronts of World War II. Following the war
1920-403: Is corrugated asbestos-cement sheets or "A/C sheets" for roofing and sidewalls. Millions of homes, factories, schools or sheds, and shelters continue to use asbestos. Cutting these sheets to size and drilling holes to receive 'J' bolts to help secure the sheets to roof framing is done on-site. There has been no significant change in production and use of A/C sheets in developing countries following
2016-457: Is disabled). The weapon fires from an open bolt . The cyclic rate can be altered by installing different bolts and recoil springs. A heavier bolt uses more recoil energy to overcome inertia, thus slowing the action. On MG 3 machine guns, two types of bolts are available, with standard weight (about 650 g (22.93 oz)) for the standard 1,000–1,200 rounds per minute cyclic rate of fire and with extra weight (about 900 g (31.75 oz)) for
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#17330850446482112-422: Is integrated with the barrel breech. During sustained firing, there is a need for the barrel to be changed and this is how they are swapped: The gun is cocked and the barrel catch on the right of the barrel shroud is swung forward. Then, the breech end of the hot barrel swings out and can be removed by elevating or twisting the gun. A fresh barrel would be inserted through the barrel catch and the muzzle bearing. When
2208-486: Is not a material covered under CERCLA 's innocent purchaser defense. In the UK, the removal and disposal of asbestos and substances containing it are covered by the Control of Asbestos Regulations 2006 . U.S. asbestos consumption hit a peak of 804,000 tons in 1973; world asbestos demand peaked around 1977, with 25 countries producing nearly 4.8 million metric tons annually. In older buildings (e.g. those built before 1999 in
2304-488: The 7.62×51mm NATO , 7.62×54mmR , 7.5×54mm French , 7.5×55mm Swiss and 7.92×57mm Mauser , and be configured for mounting to different stabilizing platforms from bipods and tripods to vehicles , aircraft , boats and fortifications , usually as an infantry support weapon or squad automatic weapon . The general-purpose machine gun (GPMG) originated with the MG 34 , designed in 1934 by Heinrich Vollmer of Mauser on
2400-595: The Bundeswehr inventory were gradually converted to the MG 3 standard. Some additional production of the MG 3 in Germany was carried out by Heckler & Koch . The MG 3 and its variants all share a high level of parts interchangeability with the original MG 42. MG 3s continue to be produced in Turkey and Pakistan. In 2019 there were plans in Germany to produce several thousand new MG 3 receivers to keep using vehicle mounted MG 3s in
2496-483: The Hindu Kush . According to Biruni in his book Gems , any cloths made of asbestos ( Persian : آذرشست , āzarshost ) were called shostakeh ( Persian : شستكه ). Some Persians believed the fiber was the fur of an animal called the samandar ( Persian : سمندر ), which lived in fire and died when exposed to water; this was where the former belief originated that the salamander could tolerate fire. Charlemagne ,
2592-511: The M60 machine gun . A mounted variant with three rotating barrels (to reduce barrel erosion and overheating) is under development as the Rheinmetall RMG 7.62 as a vehicle weapon. Only one barrel is active at a time: after one barrel overheats, it is rotated out for a cool one. The MG14z is a double barrel variant of the MG 3 machine gun with two MG 3 receivers paired together. The MG14z enhances
2688-418: The MG 1A1 (known also as the MG 42/58 ). A further development of the MG 1A1 was the MG 1A2 (known also as the MG 42/59 ), which had a heavier bolt (950 g (33.51 oz) for a slower 700–900 rounds per minute cyclic rate of fire, compared to 550 g (19.40 oz)), and a new friction ring buffer made suitable for using the heavier bolt. The MG 1A2 added new bolt-bounce preventing bolt catches to
2784-897: The Urals of the Russian Empire in the 1880s, and the Alpine regions of Northern Italy with the formation in Turin of the Italo-English Pure Asbestos Company in 1876, although this was soon swamped by the greater production levels from the Canadian mines. Mining also took off in South Africa from 1893 under the aegis of the British businessman Francis Oates, the director of the De Beers company. It
2880-542: The coaxial machine gun on numerous German tanks . During World War II , the MG 34 was supplemented by a new GPMG, the MG 42 , although it remained in combat use. The MG 42 was more efficient and cheaper to manufacture, and more robust, as well as having an extremely high cyclic rate of fire of 1,200 to 1,500 rounds per minute. One of the Einheits Maschinengewehr GPMG roles was to provide low level anti-aircraft coverage. A high cyclic rate of fire
2976-597: The 1600s, ultimately derives from the Ancient Greek : ἄσβεστος , meaning "unquenchable" or "inextinguishable". The name reflects use of the substance for wicks that would never burn up. It was adopted into English via the Old French abestos , which got the word from Greek via Latin , but in the original Greek, "asbestos" actually referred to quicklime . It is said by the Oxford English Dictionary that
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3072-592: The 1850s but were unsuccessful in creating a market for such products. Canadian samples of asbestos were displayed in London in 1862, and the first companies were formed in England and Scotland to exploit this resource. Asbestos was first used in the manufacture of yarn, and German industrialist Louis Wertheim adopted this process in his factories in Germany. In 1871, the Patent Asbestos Manufacturing Company
3168-610: The 1950s that talc products could be contaminated with asbestos. In 2020, laboratory tests of 21 talc-based cosmetics products found that 15 percent were contaminated with asbestos. In July 2024, the World Health Organization (WHO) heightened its health warning about talc exposure. In a study published in The Lancet, the WHO changed its classification of talc from "possibly carcinogenic" to "probably carcinogenic." In 2000, tests in
3264-464: The 1970s. Many buildings constructed before the 1980s contain asbestos. The use of asbestos for construction and fireproofing has been made illegal in many countries. Despite this, around 255,000 people are thought to die each year from diseases related to asbestos exposure. In part, this is because many older buildings still contain asbestos; in addition, the consequences of exposure can take decades to arise. The latency period (from exposure until
3360-528: The Chief Inspector of Factories and Workshops in the United Kingdom noted the negative health effects of asbestos, the contribution having been made by Lucy Deane Streatfeild , one of the first women factory inspectors . In 1899, H. Montague Murray noted the negative health effects of asbestos. The first documented death related to asbestos was in 1906. In the early 1900s, researchers began to notice
3456-462: The Danish C79 LMG Optic designated as M/98 apart from the standard C79 optical sight is its unique reticle of a chevron with a height of 12,5 TS and two TS line left and right with a length of 7,5 TS beginning 2,5 TS away from the tip of the chevron. The sight designated as M/99 is also available in a night vision configuration. In a stationary, heavy machine gun role the MG 3 is mounted on
3552-456: The European Union, the United Kingdom, Australia, Hong Kong, Japan, and New Zealand. A notable exception is the United States, where asbestos continues to be used in construction such as cement asbestos pipes. The 5th Circuit Court prevented the EPA from banning asbestos in 1991 because EPA research showed the ban would cost between US$ 450 and 800 million while only saving around 200 lives in
3648-639: The FERO-Z 51 night sight. A feature of the German World War II Lafette 42 tripod that was not carried over to the MG3 Feldlafette was the Tiefenfeuerautomat ("in-depth automatic fire"). If selected, this feature walked the fire in wave like motions up and down the range between predefined ranges. This sweeping of a given range ( Tiefenfeuer – "in-depth fire") continued as long as the gun
3744-461: The Libby mine was used as insulation in residential and commercial buildings through Canada and the United States. W. R. Grace and Company's loose-fill vermiculite was marketed as Zonolite but was also used in sprayed-on products such as Monokote . In 1999, the EPA began cleanup efforts in Libby and now the area is a Superfund cleanup area. The EPA has determined that harmful asbestos is released from
3840-524: The MG 1 and MG 3 ; the latter, as of 2023 , is still in production. Asbestos Asbestos ( / æ s ˈ b ɛ s t ə s , æ z -, - t ɒ s / ass- BES -təs, az-, -toss ) is a group of naturally occurring, toxic , carcinogenic and fibrous silicate minerals . There are six types, all of which are composed of long and thin fibrous crystals , each fibre ( particulate with length substantially greater than width) being composed of many microscopic "fibrils" that can be released into
3936-464: The MG 3 since 2015 with the Heckler & Koch MG5 in service. General-purpose machine gun A general-purpose machine gun ( GPMG ) is an air-cooled , usually belt -fed machine gun that can be adapted flexibly to various tactical roles for light and medium machine guns . A GPMG typically features a quick-change barrel design calibered for various fully powered cartridges such as
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4032-497: The UK, before white asbestos was banned), asbestos may still be present in some areas. Being aware of asbestos locations reduces the risk of disturbing asbestos. Removal of asbestos building components can also remove the fire protection they provide, therefore fire protection substitutes are required for proper fire protection that the asbestos originally provided. Some countries, such as India , Indonesia, China and Russia, have continued widespread use of asbestos. The most common
4128-589: The UK, the Health and Safety Executive have issued guidance called HSG264 describing how surveys should be completed although other methods can be used if they can demonstrate they have met the regulations by other means. The EPA includes some, but not all, asbestos-contaminated facilities on the Superfund National Priorities List (NPL). Renovation and demolition of asbestos-contaminated buildings are subject to EPA NESHAP and OSHA Regulations. Asbestos
4224-501: The action to resolve the ammunition ignition timing sensitivity of the preceding variants and was adapted to use both the standard German non-disintegrating Patronengurt DM1 ammunition belt and the American M13 disintegrating belt. Further improvements to the weapon's muzzle device, bipod and bolt resulted in the MG 1A3 . Simultaneously, wartime 7.92×57mm Mauser chambered MG 42 machine guns that remained in service were converted to
4320-539: The air following the buildings' destruction. Inhalation of a mixture of asbestos and other toxicants is thought to be linked to the unusually high death rate from cancer of emergency service workers since the disaster. Thousands more are now thought to be at risk of developing cancer due to this exposure with those who have died so far being only the "tip of the iceberg". In May 2002, after numerous cleanup, dust collection, and air monitoring activities were conducted outdoors by EPA, other federal agencies, New York City, and
4416-409: The amount of asbestos and the material's friable nature. Sprayed coatings, pipe insulation, and Asbestos Insulating Board (AIB) are thought to be the most dangerous due to their high content of asbestos and friable nature. Many older buildings built before the late 1990s contain asbestos. In the United States, there is a minimum standard for asbestos surveys as described by ASTM standard E 2356–18. In
4512-475: The armed forces of over 40 countries. Production rights to the machine gun were purchased by Italy ( MG 42/59 ), Spain , Pakistan (MG 1A3), Greece , Iran , Sudan and Turkey . At the end of World War II the original technical drawings and data for the 7.92×57mm Mauser chambered MG 42 were captured by the Soviets. These would later be taken to Czechoslovakia and Yugoslavia. Rheinmetall had to reverse engineer
4608-501: The atmosphere by abrasion and other processes. Inhalation of asbestos fibres can lead to various dangerous lung conditions, including mesothelioma , asbestosis , and lung cancer . As a result of these health effects, asbestos is considered a serious health and safety hazard . Archaeological studies have found evidence of asbestos being used as far back as the Stone Age to strengthen ceramic pots, but large-scale mining began at
4704-415: The barrel as after extended cyclical fire, the barrel can be dangerously hot, potentially approaching white hot. The machine gun crew member responsible for a hot barrel change is issued protective asbestos gloves or a cloth to prevent burns to the hands. The effective rate of fire is about 250 rounds per minute. The MG 3 is an automatic, air-cooled, belt-fed short recoil -operated firearm. It features
4800-484: The barrel of the MG3 after 150 live rounds (or 100 blank rounds) after sustained heavy fire, with a new, cooler one; only once the barrel is hand-warm (able to be held with the bare hand for 30 seconds) can a barrel be reused. Beneficially however, replacing the barrel is an exceptionally simple procedure on the MG3. Non-observance of this technical limitation renders the barrel prematurely unusable. Care must be taken when replacing
4896-426: The belt in two stages as the bolt moves back and forward during firing. For the light machine gun role the MG3 is equipped with a synthetic polymer stock and a folding bipod. The MG 3 has a quick-change, chrome-lined barrel with four right-hand grooves and a rifling twist rate of 1 in 305 mm (1:12 in) and weighs 1.7 kg (3.7 lb). Alternatively, MG 3 barrels can also have polygonal rifling . The barrel
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#17330850446484992-488: The bodies of their kings to preserve only their ashes and to prevent the ashes being mixed with those of wood or other combustible materials commonly used in funeral pyres . Others assert that these peoples used asbestos to make perpetual wicks for sepulchral or other lamps. A famous example is the golden lamp asbestos lychnis , which the sculptor Callimachus made for the Erechtheion . In more recent centuries, asbestos
5088-466: The catch is rotated back, the barrel is locked and the machine gun can resume firing. Both the receiver housing and ventilated barrel casing are made from pressed sheet steel. The machine gun crew member responsible for a hot barrel change is issued protective asbestos gloves to prevent getting burned. A muzzle device is mounted at the end of the barrel and it acts as a flash suppressor , muzzle brake and recoil booster. MG 3 machine guns are belt-fed from
5184-680: The commission of Nazi Germany to circumvent the restrictions on machine guns imposed by the Treaty of Versailles . It was introduced into the Wehrmacht as an entirely new concept in automatic firepower, dubbed the Einheitsmaschinengewehr , meaning "universal machine gun" in German . In itself the MG 34 was an excellent weapon for its time: an air-cooled , recoil-operated machine gun that could run through belts of 7.92×57mm Mauser ammunition at
5280-546: The detrimental effects of asbestos on human beings, examination of the primary sources reveals no support for either claim. In China, accounts of obtaining huo huan bu ( 火浣布 ) or "fire-laundered cloth" certainly dates to the Wei dynasty, and there are claims they were known as early as in the Zhou dynasty , though not substantiated except in writings thought to date much later (see huoshu or "fire rat"). Athanasius of Alexandria ,
5376-493: The diagnosis of negative health effects) is typically 20 years. The most common diseases associated with chronic asbestos exposure are asbestosis (scarring of the lungs due to asbestos inhalation) and mesothelioma (a type of cancer). Many developing countries still support the use of asbestos as a building material , and mining of asbestos is ongoing, with the top producer, Russia , having an estimated production of 790,000 tonnes in 2020. The word "asbestos", first used in
5472-440: The early 15th century, but this usage was superseded by "asbestos". The word is pronounced / æ s ˈ b ɛ s t ə s / or / æ s ˈ b ɛ s t ɒ s / . Asbestos has been used for thousands of years to create flexible objects that resist fire, including napkins, but, in the modern era, companies began producing consumer goods containing asbestos on an industrial scale. Today, the risk of asbestos has been recognized;
5568-415: The ejector bar, which hits the ejector pin. This pin pushes the top of the base of the cartridge, which is still held by the extractor at the base, causing the empty casing to rotate and eject downward through the ejection chute. The machine gun has an automatic-only trigger mechanism and a cross-bolt safety in the form of a button that is operated by the shooting hand (in its "safe" position the bolt release
5664-628: The emptied links are transported to the right. Alternatively the MG3 can also be fed by disintegrating metal M13 link belts (designated DM60 by Germany) used by many NATO member states. M13 links are also used on the Dillon M134D Minigun , M60 , FN MAG , HK21 and MG5 machine guns among others. The disintegrating metal belt is fed from the left side. Ejection of empty M13 links is to the right side, and spent cartridge cases are ejected downwards. The inexpensive M13 links are considered disposable. Both belt types are of push-through type and use
5760-488: The end of the 19th century when its diverse applications included fire-retardant coatings, concrete, bricks, pipes and fireplace cement, heat-, fire-, and acid-resistant gaskets, pipe insulation, ceiling insulation, fireproof drywall, flooring, roofing, lawn furniture, and drywall joint compound. In 2011, it was reported that over 50% of UK houses still contained asbestos, despite a ban on asbestos products some years earlier. In Japan, particularly after World War II , asbestos
5856-453: The end of the 19th century when manufacturers and builders began using asbestos for its desirable physical properties. Asbestos is an excellent thermal and electrical insulator , and is highly fire resistant, so for much of the 20th century, it was very commonly used around the world as a building material (particularly for its fire-retardant properties), until its adverse effects on human health were more widely recognized and acknowledged in
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#17330850446485952-612: The firepower of military units that still issue the MG 3 or other MG 42 derivatives. It has been developed by the Tactics Group GmbH company as "a low-cost alternative to Miniguns". The MG 3 is still used as the standard secondary weapon of most modern German armoured fighting vehicle designs (e.g. Leopard 2 , PzH 2000 , Marder ), as a primary weapon on light/non-armored vehicles (e.g. LKW 2to, MAN gl-trucks , ATF Dingo ) and as an infantry weapon on light bipods as well as different tripods. The German Armed Forces have supplemented
6048-494: The first Holy Roman Emperor (800–814), is also said to have possessed such a tablecloth. Marco Polo recounts having been shown, in a place he calls Ghinghin talas , "a good vein from which the cloth which we call of salamander, which cannot be burnt if it is thrown into the fire, is made ..." The large-scale asbestos industry began in the mid-19th century. Early attempts at producing asbestos paper and cloth in Italy began in
6144-489: The first postwar machine guns from an original MG 42 machine gun. Production of the first postwar variant of the MG 42 chambered for 7.62×51mm NATO ammunition (designated the MG 1 ) was launched in 1958 at the Rheinmetall arms factory as requested by the Bundeswehr . Shortly thereafter, the machine gun was modified, receiving a chrome -lined barrel and sights properly calibrated for the new round; this model would be named
6240-655: The left to the right side, using non-disintegrating metallic-link DM1 belts , which have links that wrap around the cartridge case and are linked by a coiling wire on each side. DM1 belts are intended for multiple reuse and in terms of design are based on and derived from the last version of the Gurt 34/41 -belt family used in World War II in MG 34 and MG 42 machine guns. DM1 belts are preloaded at ammunition factories in 50-round connectable belt lengths and can be linked to any length necessary. Spent cartridge cases are ejected downwards, and
6336-609: The low level anti-aircraft (designated MG 3A0A1) and turret mounted (designated MG 3A1A1) roles in the near future. The German military instructs that sustained fire must be avoided at all costs. In the bipod mounted light machine gun role MG 3 users are trained to fire short bursts of 3 to 5 rounds and strive to optimize their aim between bursts fired in succession. In the tripod mounted medium machine gun role, MG 3 users are trained to fire both short bursts and longer bursts of 20 to 30 rounds and strive to optimize their aim between successive bursts. The Bundeswehr trains soldiers to replace
6432-442: The lungs indicated old scarring indicative of a previous, healed tuberculosis infection, and extensive fibrosis , in which were visible "particles of mineral matter ... of various shapes, but the large majority have sharp angles." Having compared these particles with samples of asbestos dust provided by S. A. Henry, His Majesty's Medical Inspector of Factories, Cooke concluded that they "originated from asbestos and were, beyond
6528-479: The mid-1980s, and in Japan by 1995. Some products that included amphibole types of asbestos included the following: Cigarette manufacturer Lorillard ( Kent's filtered cigarette ) used crocidolite asbestos in its "Micronite" filter from 1952 to 1956. While mostly chrysotile asbestos fibers were once used in automobile brake pads , shoes, and clutch discs , contaminants of amphiboles were present. Since approximately
6624-407: The mid-1990s, brake pads, new or replacement, have been manufactured instead with linings made of ceramic, carbon, metallic, and aramid fiber ( Twaron or Kevlar —the same material used in bulletproof vests ). Artificial Christmas snow, known as flocking, was previously made with asbestos. It was used as an effect in films including The Wizard of Oz and department store window displays and it
6720-530: The mine as well as through other activities that disturb soil in the area. Talc can sometimes be contaminated with asbestos due to the proximity of asbestos ore (usually tremolite ) in underground talc deposits. By 1973, US federal law required all talc products to be asbestos-free. Separating cosmetic-grade talc (e.g. talcum powder) from industrial-grade talc (often used in friction products) has largely eliminated this issue for consumers. Cosmetics companies, including Johnson & Johnson, have known since
6816-452: The national rate. Thousands of tons of asbestos were used in World War II ships to insulate piping, boilers, steam engines, and steam turbines. There were approximately 4.3 million shipyard workers in the United States during the war; for every 1,000 workers, about 14 died of mesothelioma and an unknown number died of asbestosis. The United States government and the asbestos industry have been criticized for not acting quickly enough to inform
6912-558: The opening of the Quebec Central Railway in 1876, mining entrepreneurs such as Andrew Stuart Johnson established the asbestos industry in the province. The 50-ton output of the mines in 1878 rose to over 10,000 tonnes in the 1890s with the adoption of machine technologies and expanded production. For a long time, the world's largest asbestos mine was the Jeffrey mine in the town of Asbestos, Quebec . Asbestos production began in
7008-629: The potential as well, but asbestos may have the greatest potential and is the subject of research now in progress in an emerging field of scientific study to examine it. The most common type of asbestos, chrysotile, chemically reacts with CO 2 to produce ecologically stable magnesium carbonate . Chrysotile , like all types of asbestos, has a large surface area that provides more places for chemical reactions to occur, compared to most other naturally occurring materials. The use of asbestos in new construction projects has been banned for health and safety reasons in many developed countries or regions, including
7104-441: The public of dangers and to reduce public exposure. In the late 1970s, court documents proved that asbestos industry officials knew of asbestos dangers since the 1930s and had concealed them from the public. In Australia, asbestos was widely used in construction and other industries between 1946 and 1980. From the 1970s, there was increasing concern about the dangers of asbestos, and following community and union campaigning, its use
7200-410: The rear. The resulting impact (much like a Newton's cradle ) moves the carrier to the rear withdrawing the wedge and both rollers as they are cammed inward and out of their sockets by fixed cams, unlocking the bolt head. The bolt carrier and bolt then continue to the rear together guided by fixed guides while the barrel and barrel extension return to battery. Upon return of the bolt forward, the impact of
7296-414: The rollers against the camming surfaces on the breech carry the rollers from their seats, and, together with the surfaces on the striker sleeve, force the rollers outward, locking the bolt head into the barrel extension and ensuring a complete lock. The bolt also houses a spring-loaded casing extractor and ejector. Ejection is carried out when the ejector strikes the buffer head, sending a push forward through
7392-444: The serpentine group. In the United States, chrysotile has been the most commonly used type of asbestos. According to the U.S. Environmental Protection Agency (EPA) Asbestos Building Inspectors Manual, chrysotile accounts for approximately 95% of asbestos found in buildings in the United States. Chrysotile is often present in a wide variety of products and materials, including: In the European Union and Australia, it has been banned as
7488-474: The standard 7.62×51mm NATO chambering and designated MG 2 . In 1968, the MG 3 was introduced and entered production. Compared to the MG 1A3, the MG 3 features an improved feeding mechanism with a belt retaining pawl to hold the belt up to the gun when the top cover plate is lifted, an added anti-aircraft sight and a new ammunition box. MG 3s were produced for Germany and for export customers by Rheinmetall until 1979. The preceding non–MG 3 variant machine guns in
7584-825: The state of New York, New York City formally requested federal assistance to clean and test residences in the vicinity of the World Trade Center site for airborne asbestos. Vermiculite is a hydrated laminar magnesium-aluminum-iron silicate that resembles mica . It can be used for many industrial applications and has been used as insulation. Some deposits of vermiculite are contaminated with small amounts of asbestos. One vermiculite mine operated by W. R. Grace and Company in Libby, Montana exposed workers and community residents to danger by mining vermiculite contaminated with asbestos, typically richterite , winchite, actinolite or tremolite . Vermiculite contaminated with asbestos from
7680-418: The substance in question and then touch the fire." Wealthy Persians amazed guests by cleaning a cloth by exposing it to fire . For example, according to Tabari , one of the curious items belonging to Khosrow II Parviz, the great Sassanian king (r. 590–628), was a napkin ( Persian : منديل ) that he cleaned simply by throwing it into fire. Such cloth is believed to have been made of asbestos imported over
7776-501: The talc to the crayon makers, states that "to the best of our knowledge and belief" there had never been any asbestos-related disease among the company's workers. However media reports claim that the United States Mine Safety and Health Administration (MSHA) had found asbestos in four talc samples tested in 2000. The Assistant Secretary for Mine Safety and Health subsequently wrote to the news reporter, stating that "In fact,
7872-580: The use of asbestos is completely banned in 66 countries and strictly regulated in many others. Asbestos use dates back at least 4,500 years, when the inhabitants of the Lake Juojärvi region in East Finland strengthened earthenware pots and cooking utensils with the asbestos mineral anthophyllite ; archaeologists call this style of pottery " asbestos-ceramic ". Some archaeologists believe that ancient peoples made shrouds of asbestos, wherein they burned
7968-594: The victorious Allied nations took an interest in the MG 34 and MG 42, influencing many post-war general-purpose machine guns, many still in use today. They lent design elements to the Belgian FN MAG and the American M60 , while spawning the Zastava M53, Swiss M51, and Austrian MG 74. The MG 42's qualities of firepower and usability meant that it became the foundation of an entire series of postwar machine guns, including
8064-573: The widespread restrictions in developed nations. As New York City 's World Trade Center collapsed following the September 11 attacks , Lower Manhattan was blanketed in a mixture of building debris and combustible materials. This complex mixture gave rise to the concern that thousands of residents and workers in the area would be exposed to known hazards in the air and dust, such as asbestos, lead, glass fibers, and pulverized concrete. More than 1,000 tons of asbestos are thought to have been released into
8160-623: The word was wrongly used by Pliny for what we now call asbestos, and that he popularized the misnomer . Asbestos was originally referred to in Greek as amiantos , meaning "undefiled", because when thrown into a fire it came out unmarked. "Amiantos" is the source for the word for asbestos in many languages, such as the Portuguese amianto and the French amiante . It had also been called "amiant" in English in
8256-505: The word ἀσβεστος or ασβέστης stands consistently and solely for lime . The term asbestos is traceable to Roman naturalist Pliny the Elder 's first-century manuscript Natural History and his use of the term asbestinon , meaning "unquenchable"; he described the mineral as being more expensive than pearls . While Pliny or his nephew Pliny the Younger is popularly credited with recognising
8352-611: Was established in Glasgow , and during the following decades, the Clydebank area became a centre for the nascent industry. Industrial-scale mining began in the Thetford hills , Quebec , from the 1870s. Sir William Edmond Logan was the first to notice the large deposits of chrysotile in the hills in his capacity as head of Geological Survey of Canada . Samples of the minerals from there were displayed in London and elicited much interest. With
8448-514: Was fired. In 1974 the US Army tested German made MG3s alongside eight other contemporary GPMG designs to replace the then-in-service M219 Tank Machine Gun , which was considered unacceptably unreliable by the US Army. The MG3 had a lower Mean Rounds Between Failure than five of the candidates including the M219 and a lower Mean Rounds Between Stoppages than five of the potential replacements, notably including
8544-459: Was first used in medical literature in 1931; its association with asbestos was first noted sometime in the 1940s. Similar legislation followed in the U.S. about ten years later. Approximately 100,000 people in the United States have died, or are terminally ill, from asbestos exposure related to shipbuilding. In the Hampton Roads area, a shipbuilding center, mesothelioma occurrence is seven times
8640-587: Was from 0.03% in Brown to 1.20% in Orange . Overall, 32 different types of crayons from these brands used to contain more than trace amounts of asbestos, and eight others contained trace amounts. The Art and Creative Materials Institute , a trade association which tested the safety of crayons on behalf of the makers, initially insisted the test results must have been incorrect, although they later said they do not test for asbestos. In May 2000, Crayola said tests by Richard Lee,
8736-707: Was in South Africa that the production of amosite began in 1910. The U.S. asbestos industry had an early start in 1858 when fibrous anthophyllite was mined for use as asbestos insulation by the Johns Company, a predecessor to the current Johns Manville , at a quarry at Ward's Hill on Staten Island, New York . US production began in earnest in 1899 with the discovery of large deposits in Belvidere Mountain in Vermont. The use of asbestos became increasingly widespread toward
8832-536: Was indeed used for this purpose. A once-purported first description of asbestos occurs in Theophrastus , On Stones , from around 300 BC, but this identification has been refuted. In both modern and ancient Greek , the usual name for the material known in English as "asbestos" is amiantos ("undefiled", "pure"), which was adapted into the French as amiante and into Spanish and Portuguese as amianto . In modern Greek ,
8928-483: Was marketed for use in private homes under brand names that included "Pure White", "Snow Drift" and "White Magic". The potential for use of asbestos to mitigate climate change has been raised. Although the adverse aspects of mining of minerals, including health effects, must be taken into account, exploration of the use of mineral wastes to sequester carbon is being studied. The use of mining waste materials from nickel , copper , diamond , and platinum mines have
9024-515: Was phased out, with mining having ceased in 1983. The use of asbestos was phased out in 1989 and banned entirely in December 2003. The dangers of asbestos are now well known in Australia, and there is help and support for those suffering from asbestosis or mesothelioma. Serpentine minerals have a sheet or layered structure. Chrysotile (commonly known as white asbestos) is the only asbestos mineral in
9120-547: Was presented to Parliament on 24 March 1930. It concluded that the development of asbestosis was irrefutably linked to the prolonged inhalation of asbestos dust, and included the first health study of asbestos workers, which found that 66% of those employed for 20 years or more suffered from asbestosis. The report led to the publication of the first asbestos industry regulations in 1931, which came into effect on 1 March 1932. These rules regulated ventilation and made asbestosis an excusable work-related disease. The term mesothelioma
9216-402: Was used in the manufacture of ammonium sulfate for purposes of rice production, sprayed upon the ceilings, iron skeletons, and walls of railroad cars and buildings (during the 1960s), and used for energy efficiency reasons as well. Production of asbestos in Japan peaked in 1974 and went through ups and downs until about 1990 when production began to drop dramatically. The 1898 Annual Report of
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