Although worker exposures to lead have not been measured during high volume processing of these documents, experience dictates that there is an obvious need to take prudent measures to prevent lead exposure of these workers. A gamut of possible strategies to prevent exposure can be envisioned. If it is ever feasible to adequately clean these documents, development of appropriate cleaning methods and protection of those persons doing the cleaning are major considerations. A second strategy would be to encapsulate the documents in mylar before processing. As before, those workers encapsulating the documents must be protected from exposure. Another strategy would be to image the contaminated documents directly under conditions that would prevent or minimize worker exposure. In addition to consideration of worker protection from lead exposure, the many documents in the collection must be processed and digitized rapidly in order to make the proposed project technically and financially feasible.
The three strategies presented above can be divided into two basic approaches: 1) remove or immobilize the lead contamination and then digitize the documents, or 2) digitize contaminated documents directly. Given that all strategies must employ approximately the same effort to prevent exposure and given the potentially large number of documents that must be digitized, it is logical that the most cost-effective strategies to prevent exposure would eliminate intervening steps (encapsulating) and image the contaminated documents directly.
Dealing with contaminated documents directly would require either personal protection (respirator, gloves, coveralls, etc.) or some sort of engineering control to prevent exposure during processing. The former option may be less expensive initially, but is not conducive to high volume continuous work and, most importantly, is not a reliable means of worker protection. The latter option is initially more expensive, but if properly designed, can permit high document throughput, and is much less subject to failure. From the health and production perspective, control of the lead-contaminated dust by some sort of engineering method during processing appears to be the most attractive option.
Engineering control would involve the design of a specialized ventilation system to capture dust liberated from documents during handling. The design of the ventilation system would be based on standard and well-tested principles, but its exact form would be dictated by the processing and imaging techniques used. The system would be custom designed and fabricated; it could incorporate specialized features not used in typical ventilation systems such as use of the down-draft ventilation air flow to immobilize the document for digitization. Properly designed, such a ventilation system would eliminate the need for worker respiratory protection. Perhaps gloves would be the only personal protective equipment needed.
Additional legal and ethical constraints related to potential lead exposures of persons handling documents include training of workers about the hazards of lead, special counseling for women of reproductive age, mandated medical exams including blood lead measurements, development of a manual specifying work procedures, and training in these work procedures and the effective use of the control system. After a system is fabricated to control lead exposures, it must be fully tested before routine use; workers must wear complete protective equipment while the performance of the system is evaluated. Only after the system is found to be effective, the use of personal protective equipment can be reduced. There will also be a continuing need for periodic evaluation of the ventilation system, measurement of worker exposure to lead in the air and on surfaces, and measurement of blood lead concentrations.