and safety hazards Pastels are a dry medium and produce a great deal of dust, which can cause respiratory irritation. More seriously, pastels use the same pigments as artists' paints, many of which are toxic. For example, exposure to cadmium pigments, which are common and popular bright yellows, oranges, and reds, can lead to cadmium poisoning. Pastel artists, who use the pigments without a strong painting binder, are especially susceptible to such poisoning. For this reason, many modern pastels are made using substitutions for cadmium, chromium, and other toxic pigments, while retaining the traditional pigment names. Pastel art in art history The manufacture of pastels originated in the 15th century. The pastel medium was mentioned by Leonardo da Vinci, who learned of it from the French artist Jean Perréal after that artist's arrival in Milan in 1499. Pastel was sometimes used as a medium for preparatory studies by 16th-century artists, notably Federico Barocci. The first French artist to specialize in pastel portraits was Joseph Vivien. During the 18th century the medium became fashionable for portrait painting, sometimes in a mixed technique with gouache. Pastel was an important medium for artists such as Jean-Baptiste Perronneau, Maurice Quentin de La Tour (who never painted in oils), and Rosalba Carriera. The pastel still life paintings and portraits of Jean-Baptiste-Siméon Chardin are much admired, as are the works of the Swiss-French artist Jean-Étienne Liotard. In 18th-century England the outstanding practitioner was John Russell. In Colonial America, John Singleton Copley used pastel occasionally for portraits. In France, pastel briefly became unpopular during and after the Revolution, as the medium was identified with the frivolity of the Ancien Régime. By the mid-19th century, French artists such as Eugène Delacroix and especially Jean-François Millet were again making significant use of pastel. Their countryman Édouard Manet painted a number of portraits in pastel on canvas, an unconventional ground for the medium. Edgar Degas was an innovator in pastel technique, and used it with an almost expressionist vigor after about 1885, when it became his primary medium. Odilon Redon produced a large body of works in pastel. James Abbott McNeill Whistler produced a quantity of pastels around 1880, including a body of work relating to Venice, and this probably contributed to a growing enthusiasm for the medium in the United States. In particular, he demonstrated how few strokes were required to evoke a place or an atmosphere. Mary Cassatt,