Pottery

Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard, durable form. Major types include earthenware, stoneware and porcelain. The place where such wares are made by a "potter" is also called a "pottery" (plural "potteries"). The definition of "pottery" used by the American Society for Testing and Materials (ASTM), is "all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products." In archaeology, especially of ancient and prehistoric periods, "pottery" often means vessels only, and figures of the same material are called "terracottas." Clay as a part of the materials used is required by some definitions of pottery, but this is dubious.
Pottery is one of the oldest human inventions, originating before the Neolithic period, with ceramic objects like the Gravettian culture Venus of Dolní Věstonice figurine discovered in the Czech Republic dating back to 29,000–25,000 BC, and pottery vessels that were discovered in Jiangxi, China, which date back to 18,000 BC. Early Neolithic and pre-Neolithic pottery artifacts have been found, in Jōmon Japan (10,500 BC), the Russian Far East (14,000 BC), Sub-Saharan Africa (9,400 BC), South America (9,000s-7,000s BC), and the Middle East (7,000s-6,000s BC).
Pottery is made by forming a ceramic (often clay) body into objects of a desired shape and heating them to high temperatures (600-1600 °C) in a bonfire, pit or kiln and induces reactions that lead to permanent changes including increasing the strength and rigidity of the object. Much pottery is purely utilitarian, but much can also be regarded as ceramic art. A clay body can be decorated before or after firing.
Clay-based pottery can be divided into three main groups: earthenware, stoneware and porcelain. These require increasingly more specific clay material, and increasingly higher firing temperatures. All three are made in glazed and unglazed varieties, for different purposes. All may also be decorated by various techniques. In many examples the group a piece belongs to is immediately visually apparent, but this is not always the case. The fritware of the Islamic world does not use clay, so technically falls outside these groups. Historic pottery of all these types is often grouped as either "fine" wares, relatively expensive and well-made, and following the aesthetic taste of the culture concerned, or alternatively "coarse", "popular", "folk" or "village" wares, mostly undecorated, or simply so, and often less well-made.
Main types.
Earthenware.
The earliest forms of pottery were made from clays that were fired at low temperatures, initially in pit-fires or in open bonfires. They were hand formed and undecorated. Earthenware can be fired as low as 600 °C, and is normally fired below 1200 °C. Because unglazed biscuit earthenware is porous, it has limited utility for the storage of liquids or as tableware. However, earthenware has had a continuous history from the Neolithic period to today. It can be made from a wide variety of clays, some of which fire to a buff, brown or black colour, with iron in the constituent minerals resulting in a reddish-brown. Reddish coloured varieties are called terracotta, especially when unglazed or used for sculpture. The development of ceramic glaze made impermeable pottery possible, improving the popularity and practicality of pottery vessels. The addition of decoration has evolved throughout its history.
Stoneware.
Stoneware is pottery that has been fired in a kiln at a relatively high temperature, from about 1,100 °C to 1,200 °C, and is stronger and non-porous to liquids. The Chinese, who developed stoneware very early on, classify this together with porcelain as high-fired wares. In contrast, stoneware could only be produced in Europe from the late Middle Ages, as European kilns were less efficient, and the right type of clay less common. It remained a speciality of Germany until the Renaissance.
Stoneware is very tough and practical, and much of it has always been utilitarian, for the kitchen or storage rather than the table. But "fine" stoneware has been important in China, Japan and the West, and continues to be made. Many utilitarian types have also come to be appreciated as art.
Porcelain.
Porcelain is made by heating materials, generally including kaolin, in a kiln to temperatures between . This is higher than used for the other types, and achieving these temperatures was a long struggle, as well as realizing what materials were needed. The toughness, strength and translucence of porcelain, relative to other types of pottery, arises mainly from vitrification and the formation of the mineral mullite within the body at these high temperatures.
Although porcelain was first made in China, the Chinese traditionally do not recognise it as a distinct category, grouping it with stoneware as "high-fired" ware, opposed to "low-fired" earthenware. This confuses the issue of when it was first made. A degree of translucency and whiteness was achieved by the Tang dynasty (AD 618–906), and considerable quantities were being exported. The modern level of whiteness was not reached until much later, in the 14th century. Porcelain was also made in Korea and in Japan from the end of the 16th century, after suitable kaolin was located in those countries. It was not made effectively outside East Asia until the 18th century.
Production stages.
Before being shaped, clay must be prepared. Kneading helps to ensure an even moisture content throughout the body. Air trapped within the clay body needs to be removed. This is called de-airing and can be accomplished either by a machine called a vacuum pug or manually by wedging. Wedging can also help produce an even moisture content. Once a clay body has been kneaded and de-aired or wedged, it is shaped by a variety of techniques. After it has been shaped, it is dried and then fired.
Clay bodies and mineral contents.
Body is a term for the main pottery form of a piece, underneath any glaze or decoration. The main ingredient of the body is clay. There are several materials that are referred to as clay. The properties which make them different include:
Plasticity, the malleability of the body; the extent to which they will absorb water after firing; and shrinkage, the extent of reduction in size of a body as water is removed. Different clay bodies also differ in the way in which they respond when fired in the kiln. A clay body can be decorated before or after firing. Prior to some shaping processes, clay must be prepared. Each of these different clays is composed of different types and amounts of minerals that determine the characteristics of resulting pottery. There can be regional variations in the properties of raw materials used for the production of pottery, and these can lead to wares that are unique in character to a locality. It is common for clays and other materials to be mixed to produce clay bodies suited to specific purposes. A common component of clay bodies is the mineral kaolinite. Other minerals in the clay, such as feldspar, act as fluxes which lower the vitrification temperature of bodies. Following is a list of different types of clay used for pottery.
Methods of shaping.
Pottery can be shaped by a range of methods that include:
Decorating and glazing.
Pottery may be decorated in many different ways. Some decoration can be done before or after the firing.
Glaze.
Glaze is a glassy coating on pottery, the primary purposes of which are decoration and protection. One important use of glaze is to render porous pottery vessels impermeable to water and other liquids. Glaze may be applied by dusting the unfired composition over the ware or by spraying, dipping, trailing or brushing on a thin slurry composed of the unfired glaze and water. The colour of a glaze after it has been fired may be significantly different from before firing. To prevent glazed wares sticking to kiln furniture during firing, either a small part of the object being fired (for example, the foot) is left unglazed or, alternatively, special refractory "spurs"" are used as supports. These are removed and discarded after the firing.
Some specialised glazing techniques include:
Firing.
Firing produces irreversible changes in the body. It is only after firing that the article or material is pottery. In lower-fired pottery, the changes include sintering, the fusing together of coarser particles in the body at their points of contact with each other. In the case of porcelain, where different materials and higher firing-temperatures are used, the physical, chemical and mineralogical properties of the constituents in the body are greatly altered. In all cases, the reason for firing is to permanently harden the wares and the firing regime must be appropriate to the materials used to make them. As a rough guide, modern earthenwares are normally fired at temperatures in the range of about 1,000°C (1,830 °F) to ; stonewares at between about to ; and porcelains at between about to . Historically, reaching high temperatures was a long-lasting challenge, and earthenware can be fired effectively as low as 600°C, achievable in primitive pit firing.
Firing pottery can be done using a variety of methods, with a kiln being the usual firing method. Both the maximum temperature and the duration of firing influences the final characteristics of the ceramic. Thus, the maximum temperature within a kiln is often held constant for a period of time to "soak" the wares to produce the maturity required in the body of the wares.
The atmosphere within a kiln during firing can affect the appearance of the finished wares. An oxidising atmosphere, produced by allowing an excess of air in the kiln, can cause the oxidation of clays and glazes. A reducing atmosphere, produced by limiting the flow of air into the kiln, or burning coal rather than wood, can strip oxygen from the surface of clays and glazes. This can affect the appearance of the wares being fired and, for example, some glazes containing iron-rich minerals fire brown in an oxidising atmosphere, but green in a reducing atmosphere. The atmosphere within a kiln can be adjusted to produce complex effects in glaze.
Kilns may be heated by burning wood, coal and gas, or by electricity. When used as fuels, coal and wood can introduce smoke, soot and ash into the kiln which can affect the appearance of unprotected wares. For this reason, wares fired in wood- or coal-fired kilns are often placed in the kiln in saggars, ceramic boxes, to protect them. Modern kilns powered by gas or electricity are cleaner and more easily controlled than older wood- or coal-fired kilns and often allow shorter firing times to be used. In a Western adaptation of traditional Japanese Raku ware firing, wares are removed from the kiln while hot and smothered in ashes, paper or woodchips which produces a distinctive carbonised appearance. This technique is also used in Malaysia in creating traditional "labu sayung".
In Mali, a firing mound is used rather than a brick or stone kiln. Unfired pots are first brought to the place where a mound will be built, customarily by the women and girls of the village. The mound's foundation is made by placing sticks on the ground, then:
History.
A great part of the history of pottery is prehistoric, part of past pre-literate cultures. Therefore, much of this history can only be found among the artifacts of archaeology. Because pottery is so durable, pottery and shards of pottery survive from millennia at archaeological sites, and are typically the most common and important type of artifact to survive. Many prehistoric cultures are named after the pottery that is the easiest way to identify their sites, and archaeologists develop the ability to recognise different types from the chemistry of small shards.
Before pottery becomes part of a culture, several conditions must generally be met.
History by region.
Beginnings of pottery.
Pottery may well have been discovered independently in various places, probably by accidentally creating it at the bottom of fires on a clay soil. All the earliest vessel forms were pit fired and made by coiling, which is a simple technology to learn. The earliest-known ceramic objects are Gravettian figurines such as those discovered at Dolní Věstonice in the modern-day Czech Republic. The Venus of Dolní Věstonice is a Venus figurine, a statuette of a nude female figure dated to 29,000–25,000 BC (Gravettian industry).
Sherds have been found in China and Japan from a period between 12,000 and perhaps as long as 18,000 years ago. As of 2012, the earliest pottery found anywhere in the world, dating to 20,000 to 19,000 years before the present, was found at Xianrendong Cave in the Jiangxi province of China.
Other early pottery vessels include those excavated from the Yuchanyan Cave in southern China, dated from 16,000 BC, and those found in the Amur River basin in the Russian Far East, dated from 14,000 BC.
The Odai Yamamoto I site, belonging to the Jōmon period, currently has the oldest pottery in Japan. Excavations in 1998 uncovered earthenware fragments which have been dated as early as 14,500 BC.
The term "Jōmon" means "cord-marked" in Japanese. This refers to the markings made on the vessels and figures using sticks with cords during their production. Recent research has elucidated how Jōmon pottery was used by its creators.
It appears that pottery was independently developed in Sub-Saharan Africa during the 10th millennium BC, with findings dating to at least 9,400 BC from central Mali, and in South America during the 9,000s-7,000s BC. The Malian finds date to the same period as similar finds from East Asia – the triangle between Siberia, China and Japan – and are associated in both regions to the same climatic changes (at the end of the ice age new grassland develops, enabling hunter-gatherers to expand their habitat), met independently by both cultures with similar developments: the creation of pottery for the storage of wild cereals (pearl millet), and that of small arrowheads for hunting small game typical of grassland. Alternatively, the creation of pottery in the case of the Incipient Jōmon civilisation could be due to the intensive exploitation of freshwater and marine organisms by late glacial foragers, who started developing ceramic containers for their catch.
East Asia.
In Japan, the Jōmon period has a long history of development of Jōmon pottery which was characterized by impressions of rope on the surface of the pottery created by pressing rope into the clay before firing. Glazed Stoneware was being created as early as the 15th century BC in China. A form of Chinese porcelain became a significant Chinese export from the Tang Dynasty (AD 618–906) onwards. Korean potters adopted porcelain as early as the 14th century AD. Japanese porcelain was made in the early 16th century after Shonzui Goradoyu-go brought back the secret of its manufacture from the Chinese kilns at Jingdezhen.
In contrast to Europe, the Chinese elite used pottery extensively at table, for religious purposes, and for decoration, and the standards of fine pottery were very high. From the Song dynasty (960–1279) for several centuries elite taste favoured plain-coloured and exquisitely formed pieces; during this period true porcelain was perfected in Ding ware, although it was the only one of the Five Great Kilns of the Song period to use it. The traditional Chinese category of high-fired wares includes stoneware types such as Ru ware, Longquan celadon, and Guan ware. Painted wares such as Cizhou ware had a lower status, though they were acceptable for making pillows.
The arrival of Chinese blue and white porcelain was probably a product of the Mongol Yuan dynasty (1271–1368) dispersing artists and craftsmen across its large empire. Both the cobalt stains used for the blue colour, and the style of painted decoration, usually based on plant shapes, were initially borrowed from the Islamic world, which the Mongols had also conquered. At the same time Jingdezhen porcelain, produced in Imperial factories, took the undisputed leading role in production, which it has retained to the present day. The new elaborately painted style was now favoured at court, and gradually more colours were added.
The secret of making such porcelain was sought in the Islamic world and later in Europe when examples were imported from the East. Many attempts were made to imitate it in Italy and France. However it was not produced outside of the Orient until 1709 in Germany.
South Asia.
Cord-Impressed style pottery belongs to 'Mesolithic' ceramic tradition that developed among Vindhya hunter-gatherers in Central India during the Mesolithic period. This ceramic style is also found in later Proto-Neolithic phase in nearby regions. This early type of pottery, also found at the site of Lahuradewa, is currently the oldest known pottery tradition in South Asia, dating back to 7,000-6,000 BC. Wheel-made pottery began to be made during the Mehrgarh Period II (5,500–4,800 BC) and Merhgarh Period III (4,800–3,500 BC), known as the ceramic Neolithic and chalcolithic. Pottery, including items known as the ed-Dur vessels, originated in regions of the Saraswati River / Indus River and have been found in a number of sites in the Indus Civilization.
Despite an extensive prehistoric record of pottery, including painted wares, little "fine" or luxury pottery was made in the subcontinent in historic times. Hinduism discourages eating off pottery, which probably largely accounts for this. Most traditional Indian pottery vessels are large pots or jars for storage, or small cups or lamps, often treated as disposable. In contrast there are long traditions of sculpted figures, often rather large, in terracotta.
Southeast Asia.
Pottery in Southeast Asia is as diverse as its ethnic groups. Each ethnic group has their own set of standards when it comes to pottery arts. Potteries are made due to various reasons, such as trade, food and beverage storage, kitchen usage, religious ceremonies, and burial purposes.
Near East.
Around 8000 BC during the Pre-pottery Neolithic period, and before the invention of pottery, several early settlements became experts in crafting beautiful and highly sophisticated containers from stone, using materials such as alabaster or granite, and employing sand to shape and polish. Artisans used the veins in the material to maximum visual effect. Such objects have been found in abundance on the upper Euphrates river, in what is today eastern Syria, especially at the site of Bouqras.
The earliest history of pottery production in the Fertile Crescent starts the Pottery Neolithic and can be divided into four periods, namely: the Hassuna period (7000–6500 BC), the Halaf period (6500–5500 BC), the Ubaid period (5500–4000 BC), and the Uruk period (4000–3100 BC). By about 5000 BC pottery-making was becoming widespread across the region, and spreading out from it to neighbouring areas.
Pottery making began in the 7th millennium BC. The earliest forms, which were found at the Hassuna site, were hand formed from slabs, undecorated, unglazed low-fired pots made from reddish-brown clays. Within the next millennium, wares were decorated with elaborate painted designs and natural forms, incising and burnished.
The invention of the potter's wheel in Mesopotamia sometime between 6000 and 4000 BC (Ubaid period) revolutionized pottery production. Newer kiln designs could fire wares to to which enabled new possibilities and new preparation of clays. Production was now carried out by small groups of potters for small cities, rather than individuals making wares for a family. The shapes and range of uses for ceramics and pottery expanded beyond simple vessels to store and carry to specialized cooking utensils, pot stands and rat traps. As the region developed, new organizations and political forms, pottery became more elaborate and varied. Some wares were made using moulds, allowing for increased production for the needs of the growing populations. Glazing was commonly used and pottery was more decorated.
In the Chalcolithic period in Mesopotamia, Halafian pottery achieved a level of technical competence and sophistication, not seen until the later developments of Greek pottery with Corinthian and Attic ware.
Europe.
The early inhabitants of Europe developed pottery in the Linear Pottery culture slightly later than the Near East, circa 5500–4500 BC. In the ancient Western Mediterranean elaborately painted earthenware reached very high levels of artistic achievement in the Greek world; there are large numbers of survivals from tombs. Minoan pottery was characterized by complex painted decoration with natural themes. The classical Greek culture began to emerge around 1000 BC featuring a variety of well crafted pottery which now included the human form as a decorating motif. The pottery wheel was now in regular use. Although glazing was known to these potters, it was not widely used. Instead, a more porous clay slip was used for decoration. A wide range of shapes for different uses developed early and remained essentially unchanged during Greek history. 
Fine Etruscan pottery was heavily influenced by Greek pottery and often imported Greek potters and painters. Ancient Roman pottery made much less use of painting, but used moulded decoration, allowing industrialized production on a huge scale. Much of the so-called red Samian ware of the Early Roman Empire was in fact produced in modern Germany and France, where entrepreneurs established large potteries. Excavations at Augusta Raurica, near Basel, Switzerland, have revealed a pottery production site in use from the 1st to the 4th century AD. 
Pottery was hardly seen on the tables of elites from Hellenistic times until the Renaissance, and most medieval wares were coarse and utilitarian, as the elites ate off metal vessels. Painted Hispano-Moresque ware from Spain, developing the styles of Islamic Spain, became a luxury for late medieval elites, and was adapted in Italy into "maiolica" in the Italian Renaissance. Both of these were faience or tin-glazed earthenware, and fine faience continued to be made until around 1800 in various countries, especially France, with Nevers faience and several other centres. In the 17th century, imports of Chinese export porcelain and its Japanese equivalent raised the market 
expectations of fine pottery, and European manufacturers eventually learned to make porcelain, often in the form of "artificial" or soft-paste porcelain, and from the 18th century European porcelain and other wares from a great number of producers became extremely popular, reducing Asian imports.
United Kingdom.
The English city of Stoke-on-Trent is widely known as "The Potteries" because of the large number of pottery factories or, colloquially, "Pot Banks." It was one of the first industrial cities of the modern era where, as early as 1785, two hundred pottery manufacturers employed 20,000 workers. Josiah Wedgwood (1730–1795) was the dominant leader.
In North Staffordshire hundreds of companies produced all kinds of pottery, from tablewares and decorative pieces to industrial items. The main pottery types of earthenware, stoneware and porcelain were all made in large quantities, and the Staffordshire industry was a major innovator in developing new varieties of ceramic bodies such as bone china and jasperware, as well as pioneering transfer printing and other glazing and decorating techniques. In general Staffordshire was strongest in the middle and low price ranges, though the finest and most expensive types of wares were also made.
By the late 18th century North Staffordshire was the largest producer of ceramics in Britain, despite significant centres elsewhere. Large export markets took Staffordshire pottery around the world, especially in the 19th century. Production had begun to decline in the late 19th century, as other countries developed their industries, and declined steeply after World War II. Some production continues in the area, but at a fraction of the levels at the peak of the industry.
Islamic pottery.
Early Islamic pottery followed the forms of the regions which the Muslims conquered. Eventually, however, there was cross-fertilization between the regions. This was most notable in the Chinese influences on Islamic pottery. Trade between China and Islam took place via the system of trading posts over the lengthy Silk Road. Islamic nations imported stoneware and later porcelain from China. China imported the minerals for Cobalt blue from the Islamic ruled Persia to decorate their blue and white porcelain, which they then exported to the Islamic world.
Likewise, Islamic art contributed to a lasting pottery form identified as Hispano-Moresque in Andalucia (Islamic Spain). Unique Islamic forms were also developed, including fritware, lusterware and specialized glazes like tin-glazing, which led to the development of the popular maiolica.
One major emphasis in ceramic development in the Muslim world was the use of tile and decorative tilework.
Americas.
Most evidence points to an independent development of pottery in the Native American cultures, with the earliest known dates from Brazil, from 9,500 to 5,000 years ago and 7,000 to 6,000 years ago. Further north in Mesoamerica, dates begin with the Archaic Era (3500–2000 BC), and into the Formative period (2000 BC – AD 200). These cultures did not develop the stoneware, porcelain or glazes found in the Old World. Maya ceramics include finely painted vessels, usually beakers, with elaborate scenes with several figures and texts. Several cultures, beginning with the Olmec, made terracotta sculpture, and sculptural pieces of humans or animals that are also vessels are produced in many places, with Moche portrait vessels among the finest.
Africa.
Evidence indicates an independent invention of pottery in Sub-Saharan Africa. In 2007, Swiss archaeologists discovered pieces of the oldest pottery in Africa at Ounjougou in Central Mali, dating back to at least 9,400 BC. In later periods, a relationship of the introduction of pot-making in some parts of Sub-Saharan Africa with the spread of Bantu languages has been long recognized, although the details remain controversial and awaiting further research, and no consensus has been reached.
Ancient Egyptian pottery begins after 5,000 BC, having spread from the Levant. There were many distinct phases of development in pottery, with very sophisticated wares being produced by the Naqada III period, c. 3,200 to 3,000 BC. During the early Mediterranean civilizations of the fertile crescent, Egypt developed a non-clay-based ceramic which has come to be called Egyptian faience. A similar type of body is still made in Jaipur in India. During the Umayyad Caliphate of Islam, Egypt was a link between early centre of Islam in the Near East and Iberia which led to the impressive style of pottery.
It is, however, still valuable to look into pottery as an archaeological record of potential interaction between peoples, especially in areas where little or no written history exists. Because Africa is primarily heavy in oral traditions, and thus lacks a large body of written historical sources, pottery has a valuable archaeological role. When pottery is placed within the context of linguistic and migratory patterns, it becomes an even more prevalent category of social artifact. As proposed by Olivier P. Gosselain, it is possible to understand ranges of cross-cultural interaction by looking closely at the "chaîne opératoire" of ceramic production.
The methods used to produce pottery in early Sub-Saharan Africa are divisible into three categories: techniques visible to the eye (decoration, firing and post-firing techniques), techniques related to the materials (selection or processing of clay, etc.), and techniques of molding or fashioning the clay. These three categories can be used to consider the implications of the reoccurrence of a particular sort of pottery in different areas. Generally, the techniques that are easily visible (the first category of those mentioned above) are thus readily imitated, and may indicate a more distant connection between groups, such as trade in the same market or even relatively close proximity in settlements. Techniques that require more studied replication (i.e., the selection of clay and the fashioning of clay) may indicate a closer connection between peoples, as these methods are usually only transmissible between potters and those otherwise directly involved in production. Such a relationship requires the ability of the involved parties to communicate effectively, implying pre-existing norms of contact or a shared language between the two. Thus, the patterns of technical diffusion in pot-making that are visible via archaeological findings also reveal patterns in societal interaction.
Oceania.
Polynesia, Melanesia and Micronesia
Pottery has been found in archaeological sites across the islands of Oceania. It is attributed to an ancient archaeological culture called the Lapita. Another form of pottery called Plainware is found throughout sites of Oceania. The relationship between Lapita pottery and Plainware is not altogether clear.
The Indigenous Australians never developed pottery. After Europeans came to Australia and settled, they found deposits of clay which were analysed by English potters as excellent for making pottery. Less than 20 years later, Europeans came to Australia and began creating pottery. Since then, ceramic manufacturing, mass-produced pottery and studio pottery have flourished in Australia.
Archaeology.
The study of pottery can help to provide an insight into past cultures. Pottery is durable, and fragments, at least, often survive long after artefacts made from less-durable materials have decayed past recognition. Combined with other evidence, the study of pottery artefacts is helpful in the development of theories on the organisation, economic condition and the cultural development of the societies that produced or acquired pottery. The study of pottery may also allow inferences to be drawn about a culture's daily life, religion, social relationships, attitudes towards neighbours, attitudes to their own world and even the way the culture understood the universe.
Chronologies based on pottery are often essential for dating non-literate cultures and are often of help in the dating of historic cultures as well. Trace-element analysis, mostly by neutron activation, allows the sources of clay to be accurately identified and the thermoluminescence test can be used to provide an estimate of the date of last firing. Examining fired pottery shards from prehistory, scientists learned that during high-temperature firing, iron materials in clay record the exact state of Earth's magnetic field at that exact moment.
Health and environmental issues in production.
Although many of the environmental effects of pottery production have existed for millennia, some of these have been amplified with modern technology and scales of production. The principal factors for consideration fall into two categories: (a) effects on workers, and (b) effects on the general environment.
The chief risks on worker health include heavy metal poisoning, poor indoor air quality, dangerous sound levels and possible over-illumination.
Historically, "plumbism" (lead poisoning) was a significant health concern to those glazing pottery. This was recognised at least as early as the nineteenth century, and the first legislation in the United Kingdom to limit pottery workers' exposure was introduced in 1899.
Proper ventilation to guarantee adequate indoor air quality can reduce or eliminate workers' exposure to fine particulate matter, carbon monoxide, certain heavy metals, and crystalline silica (which can lead to silicosis). A more recent study at Laney College, Oakland, California suggests that all these factors can be controlled in a well-designed workshop environment.
The primary environmental concerns include off-site water pollution, air pollution, disposal of hazardous materials, and fuel consumption.