paper can be supplied collated either in pads or books bound into sets, or as loose sets, or as continuous stationery for printers designed to use it. Dyes and chemicals The first dye used commercially in this application was crystal violet lactone, which is widely used today. Other dyes and supporting chemicals used are PTSMH (p-toluene sulfinate of Michler's hydrol), TMA (trimellitic anhydride), phenol-formaldehyde resins, azo dyes, DIPN (diisopropylnaphthalenes, formaldehyde isocyanates, hydrocarbon-based solvents, polycyclic aromatic hydrocarbons, polyoxypropylene diamine, epoxy resins, aliphatic isocyanates, bisphenol A, diethylene triamine, and others. The dyes in carbonless copy papers may cause contact dermatitis in sensitive persons. Health and environmental concerns Until the 1970s, when the use of polychlorinated biphenyls (PCBs) was banned due to health and environmental concerns, PCBs were used as a transfer agent in carbonless copy paper. PCBs are readily transferred to human skin during handling of such papers, and it is difficult to achieve decontamination by ordinary washing with soap and water. In Japan, carbonless copy paper is still treated as a PCB-contaminated waste. Exposure to certain types of carbonless copy paper or its components has resulted, under some conditions, in mild to moderate symptoms of skin irritation and irritation of the mucosal membranes of the eyes and upper respiratory tract. A 2000 review found no irritation or sensitization on contact with carbonless copy paper produced after 1987. In most cases, good industrial hygiene and work practices should be adequate to reduce or eliminate symptoms. These include adequate ventilation, humidity, and temperature controls; proper housekeeping; minimal hand-to-mouth and hand-to-eye contact; and periodic cleansing of hands. In a 1997 study, the University of Florida found that a poorly-ventilated office where large amounts of carbonless copy paper were used had significant levels of volatile organic compounds present in its air, whereas a well-ventilated office where little such paper was used did not. The study also found that there were higher rates of sick leave and illness complaints at the office using large amounts of carbonless copy paper. Another study, which was published in Environmental Health Perspectives, connected chronic occupational exposure to paper dust and carbonless copy paper with an increased risk of adult-onset asthma. The average carbonless copy paper contains a high concentration of bisphenol A (BPA), an endocrine disruptor. In 2001, three employees of a medical center in San Francisco filed a lawsuit against their employer, blaming exposure to carbonless copy paper and