Contamination: Invisible And Airborne

Dec 01, 2011


Mark Dalziel. Managing director at Dycem Ltd
Millions of pounds worth of products are at risk if contamination occurs in a cleanroom environment. According to an independent consultant (Cleanroom Management Associates Inc) for our company, contamination from personnel and equipment, such as wheeled carts and tanks, is a major concern in cleanrooms and controlled environments.

The consequences of contamination are severe. A single microbe in a batch of aseptic drugs could cause the entire batch to be quarantined or scrapped, leading to supply shortages, financial consequences, product recalls, FDA warning letters or even company shutdown in the worst case scenario.

High levels of air-borne contamination can lead to microbial corruption of cleanroom surfaces. By their very nature, the movement of airborne contaminants is volatile, which makes detection and prevention measures difficult. Contaminants are generated by people, process, facilities and equipment, and must be continually controlled and removed from the air.

Particles outside critical areas are a potential problem because they are not easily detectable, particularly small, light, invisible particles. Even loose particles that settle on the floor can be easily crushed into very small particles and redistributed back into the air due to vortices created by movement. These airborne particles become suspended in the air and get carried into the critical area where they present a potential hazard. Such particles are difficult to control because they are hard to see with the naked eye.

Contamination control

An effective contamination control regime should be put in place. ISO cleanroom standards recommend and cGMP necessitates that the introduction of particles into critical areas is minimised.

Effective contamination control requires a progressive zonal approach. Areas that are critical to maintaining cleanroom zones are entrances and exits; any areas used or inhabited by personnel, particularly gowning and staff changing areas and airlocks. Organisations also need to monitor and ensure that effective decontamination measures are in place in any areas where equipment, trolleys or tanks are moved.