A call to arms

What do we do when a cornerstone of our contamination control arsenal is identified as 'not meeting expectations?' In July 1999, the American Journal of Health-System Pharmacy (1) published an article reporting surface contamination while using Class II biological safety cabinets during the preparation of antineoplastic agents.

The contamination was documented in five locations outside of the Class II biological safety cabinets. All six cancer centers involved in the study reported the presence of the antineoplastic agents.

To contamination control experts and industrial hygiene professionals, this is a call to arms! Technology has failed us! However, disbelief was the response I received when sharing this information with those in the industrial hygiene and contamination control industry. As with any information that is inconsistent with conventional wisdom, first there was denial, then suspicion of the source, which was followed by rationalization.

The denial and suspicion of source is easily dealt with, because the information contained in the study was gathered in a professional manner [See “Contaminants found outside Class II BSCs,” page 1]. The study contained observations well organized and gathered using a controlled method. The source of the information was respected professionals in pharmacy, industrial hygiene and exposure control from the United States, Canada and Europe. One of the individuals, Dr. Roger Anderson, was instrumental in the movement to Class II cabinets for handling antineoplastic agents almost two decades ago.

The data indicated concentrations of antineoplastic agents exceeding exposure guidelines in five locations outside the Class II cabinets. The location, validation of sampling method and number of points sampled confirms that the material is present in significant quantities in the pharmacy.

When confronted with something that does not fit our paradigm, rationalization is the next normal reaction. How can we explain this information without destroying the belief in our cornerstone of contamination control, the Class II biological safety cabinet? “It must be operator error! Work practices are at fault, they just do not know how to do their job!”

The data indicates that all sites showed levels of the antineoplastic agents at most of the locations monitored. We must recognize a major problem exists that could impact the thousands of individuals working in cancer centers, hospitals and oncology offices throughout the world. Most of those at risk are not aware of the increasing information confirming the lack of protection by the Class II biological safety cabinet.

Several theories have been expressed regarding the source of the contamination:

  • Vapors are formed because of pressure differential in the transfer of the antineoplastic liquids via syringe. The vapors are small and cannot be captured by the HEPA filters.
  • The transfer of materials into and out of the open face of the biological safety cabinet combined with operator movement into and out of the cabinet disturbs air flows thereby “dragging” contamination out of the cabinet.
  • Training is the problem. Poor technique is the cause of contamination.

Understanding the source of the contamination is the first step toward developing a solution. Let me know your thoughts on the source, and I'll report more in a future edition of CleanRooms.


  1. American Journal of Health-System Pharmacy, Surface contamination with antineoplastic agents in six cancer treatment centers, Vol. 56 Number 14, July 15, 1999, p1427-1432.

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Hank Rahe is director of technology at Contain-Tech in Indianapolis. He has over 30 years' experience in the healthcare industry. 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.


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