Cross contamination of products by live biologicals, or by drug products, such as certain steroids or cytotoxic agents which in trace amounts may produce physiological effects should be prevented by the following methods:

1 carrying out production operations in separate buildings or adequately isolating the operations by total enclosure 2 controlling airborne contaminants by the use of an appropriate air pressure differential in processing areas and adequate exhaust systems and filters, together with control of recirculated air 3 the setting and shielding of production equipment, and wherever possible, the use of equipment solely for one type of drug/product; 4 containment of contaminant-transfer by means of airlocks, clothing change and decontamination of containers and other articles prior to their removal from the isolated area 5 separate cleaning area for contaminated clothing 6 periodic testing of the environment around the production areas for the presence of the therapeutic substance being processed and 7 validation of cleaning procedures.