in the face of environmental clean air restrictions was in the production of salt-glazed sewer-pipes. Ash glazing – ash from the combustion of plant matter has been used as the flux component of glazes. The source of the ash was generally the combustion waste from the fuelling of kilns although the potential of ash derived from arable crop wastes has been investigated. Ash glazes are of historical interest in the Far East although there are reports of small-scale use in other locations such as the Catawba Valley Pottery in the United States. They are now limited to small numbers of studio potters who value the unpredictability arising from the variable nature of the raw material. Health and environmental issues 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: Effects on workers. Notable risks include silicosis, heavy metal poisoning, poor indoor air quality, dangerous sound levels and possible over-illumination. Effects on the general environment. Historically, lead poisoning (plumbism) was a significant health concern to those glazing pottery. This was recognised at least as early as the nineteenth century. The first legislation in the UK to limit pottery workers' exposure to lead was included in the Factories Act Extension Act in 1864, with further introduced in 1899. Silicosis is an occupational lung disease caused by inhaling large amounts of crystalline silica dust, usually over many years. Workers in the ceramic sector can develop it due to exposure to silica dust in the raw materials; colloquially it has been known as 'Potter's rot'. In one study reported in 2022, of 106 UK pottery workers 55 per cent had at least some stage of silicosis. Proper ventilation to ensure adequate indoor air quality can reduce or eliminate workers' exposure to crystalline silica, as well as other particulate matter, carbon monoxide and certain heavy metals. A relatively recent study suggested that all these factors can be controlled in a well-designed studio. The Health and Safety Executive in the UK has produced guidelines on controlling exposure to respirable crystalline silica in potteries, and the British Ceramics Federation provide, as a free download, a booklet. Environmental concerns include off-site water pollution, air pollution, disposal of hazardous materials, disposal of rejected ware and fuel consumption. History A great part of the history