This is a special guest editorial from our regular columnists, Barbara and Ed Kanegsberg
WONDERFUL, CONFLICTING, and exasperating trends are occurring in the field of contamination control. There is a demand to know more and more about less and less in terms of overall level, identification, and toxicity; and there is a demand for zero risk in any proposed process or activity. We have come to think of the demand for greater identification of potential contaminants combined with impatience with incomplete data and intolerance of any risk as the “Kanegsberg uncertainty principle.”
Specifically, there is a demand for increased detail about surface properties and potential surface contaminants. Increasingly sensitive and specific analytical techniques permit the accumulation of daunting amounts of data about the surface of any given critical product. Who demands this information? Demands (or strong requests) come not only from technical people within companies, but also from company lawyers and from agencies such as the EPA, the FDA, and the DOD.
While we may be able to identify lower and lower levels of individual contaminants, we do not always know what to do with that information. With the demand for more analytical information comes the quest for absolute safety, for absolute certainty. We all want not just assurance, but absolute certainty that anything found on the surface of a product will cause no potential issues for the worker, the environment, or, especially in the case of medical devices, to the end-user. Given the increasing numbers of diverse materials of construction and process chemicals and given the limited number of toxicity studies that have been performed, we are highly unlikely to know everything about potential risks of a given residue, let alone the potential non-additive risks of multiple residues.
It is a good idea to worry about contaminants and about surface properties, but not to the extent that we are unable to move forward with new product, and not to the extent of precluding any modification in surface preparation. We will never know with absolute certainty that any particular molecules found on a surface are harmful, or that they are perhaps potentially beneficial.
Attempting to freeze processes in place and to never allow changes, in the manner of Oliver Wendell Holmes’ “The Deacon’s Masterpiece” (also known as the “One-Hoss Shay”) is unrealistic and counterproductive. With increasingly stringent production and regulatory requirements, change is inevitable. Further, we cannot totally rely on extrapolation from historical data, because as miniature and nano-scale devices are developed, novel cleaning and analytical techniques will need to be employed.
Standards, cleaning protocols, and official positions are helpful in making process decisions. Using a standard or protocol as a protective shield is not likely to result in a better product. Definitive decisions concerning contamination are likely to remain process-specific. At the same time, standards and the processes of developing standards (including the inevitable disagreements) provide a common basis of understanding that expedites our understanding of contamination issues.
When asked for absolute assurance about the nature and potential consequences of residue, the most realistic answer we can provide is that absolute certainty is impossible. While discussing unknown and perhaps unknowable aspects of cosmology, Brian Greene succinctly states in his book The Elegant Universe, “sometimes attaining the deepest familiarity with a question is our best substitute for actually having the answer.” In contamination control, the best approachis not to expect certainty, but rather to continue to understand the questions.