This testimony concerns the final comments of NIOSH on OSHA's proposed rule on bloodborne pathogens. The risks to health posed by hepatitis-B virus (HBV), human immunodeficiency virus (HIV), and other bloodborne diseases clearly warrant development and enforcement by OSHA of a comprehensive standard. As of May 15, 1990, the Centers for Disease Control were aware of 65 case reports of health care workers who may have acquired HIV infection from occupational exposure. Twenty seroconverted following a documented occupational exposure. Of these 20, 18 involved exposure to blood, one to bloody pleural fluid, and one to concentrated virus in the laboratory. Vaccination is the single most effective means of preventing occupational HBV transmission. However, about 5% of those given vaccination do not develop an antibody response and remain susceptible. Questions remain about the efficacy of gloves for offering protection. Other areas discussed include the use of signs and labels, post exposure evaluation and follow up of exposed workers.