Since 1975, Thea B. van Oosten has been employed as a conservation scientist at the Cultural Heritage Agency of the Netherlands (RCE). In 1989 she started as senior conservation scientist the research programme on plastics and she has been developing that ever since. Specialised in the conservation of modern and contemporary art and design objects of Cultural Heritage, she has contributed to several publications and books such as ‘PUR Facts, Conservation of Polyurethane foam in Art and Design’. She further tries to disseminate her knowledge and experience by teaching courses and workshops and giving lectures on this topic both in the Netherlands and in various workshops around the world. Since July 2011 she is on retirement and is working as a freelance conservation scientist.