Containment strategy is a moving target
10/01/2001
by Hank Rahe
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Containment strategies have become moving targets due to the changing acceptable exposure limits for new compounds. Exposure limits of 10 micrograms were the exception five years ago, but today it is not uncommon for new compounds to have exposure limits in the low nanogram range.
How does this impact your company's contamination control strategy? When the low exposure limits were in the microgram range, operations such as laboratories were of less concern because they handled only small quantities of materials; and if the weighing operation was controlled, the major potential for exposure was satisfied. With exposure levels in the nanogram range, a one-gram sample is a large quantity of material.
Transfer of sample quantities, preparation of testing materials and even the actual testing operations now represent a significant exposure potential. The use of conventional open bench-top instruments with samples prepared in hoods is becoming unacceptable. To protect against these low exposure levels, companies must conduct a detailed evaluation of laboratory operations to determine if an over-exposure potential exists.
A complete evaluation of the laboratory should begin with the receipt of the samples and a flow of the materials through the laboratory operations just as if it were a process. Containers in which the samples are received should be evaluated to determine if they are compatible with the subdividing operations and if they have proper secondary protection in case they are accidentally dropped.
The highest potential exists in sample preparation where the potent compound is subdivided and solutions are prepared for testing. This operation involves an open container and manual manipulation of the powder.
This area should have engineering controls capable of containing the powder; but in many cases, the devices used for this operation are not designed for handling powders and can represent more risk than benefit.
Many operations within the laboratory use a solution for testing which reduces the potential for exposure. However, in some cases, the instruments can place the solution under pressure, which can cause the potent materials to become airborne as an aerosol.
Each testing operation should be evaluated for a potential exposure point.
Disposal of the remainder of the potent compound sample after testing can also become an issue. Often, the quantity collected after testing is much greater than the amount used in the testing. The disposal of trash containers that may contain many different potent compounds requires special handling and proper labeling.
Custodial personnel should be made aware of the hazardous nature of the materials. "Attractive Trash" is an issue because individuals both on and off site can be attracted to plastic bags, containers and other items contained in the trash for secondary usage.
Exposure levels of potent compounds in the nanogram range require companies to do a detailed analysis of every activity and location where the potent compound is handled and stored to determine if any potential exists for exposure.
Laboratory operations, transportation, storage and disposal of sample quantities can become major risk points in handling of the compounds. Each requires a complete evaluation to ensure that proper engineering controls, personnel training and procedures are implemented.
Hank Rahe is director of technology at Contain-Tech in Indianapolis. He has over 30 years' experience in the healthcare industry, as well as four years in academia. He is an expert in the areas of conventional and advanced aseptic processing. He is the past chairman of the board of the International Society of Pharmaceutical Engineers, and is a member of the CleanRooms Editorial Advisory Board.