Use Overshoes When Entering Grade C Cleanroom Areas

Remember: Wearing overshoes before entering Grade C zones is a mandatory step in cleanroom gowning to minimize contamination from external footwear.

Why This Matters in GMP

Footwear is a significant vector for introducing external contaminants—dust, microbes, debris—into controlled manufacturing environments. Grade C areas, commonly used for non-aseptic cleanroom operations like formulation and equipment staging, demand a high level of cleanliness to maintain product safety and environmental control. Overshoes, typically disposable and sterile or cleanroom-certified, act as a physical barrier that prevents contamination from being tracked into the clean area. Omitting this gowning step compromises the effectiveness of cleanroom controls and increases the bioburden, which can lead to deviations during environmental monitoring or product testing. This seemingly small oversight can ultimately jeopardize product quality and compliance.

Regulatory and Compliance Implications

Gowning procedures, including the use of overshoes, are clearly defined within international GMP frameworks as essential contamination control strategies. Under FDA 21 CFR Part 211.28, personnel engaged in the manufacture of drug products must wear clean protective apparel appropriate to the duties they perform. This includes adequate covering of the body and footwear to ensure protection against contamination. The EU GMP Annex 1 provides even more specific requirements for gowning in different classified areas. For Grade C areas, the annex mandates that personnel wear clean, sterilized (if necessary) overshoes and that the gowning process be sequenced to avoid recontamination.

The WHO GMP guidelines also call for protective clothing appropriate to the working area, specifying footwear coverage as a key part of personal hygiene. In addition, Schedule M of the Indian GMP framework requires facilities to have controlled entry procedures into processing areas, including adequate gowning practices like overshoes to protect cleanroom integrity. Regulatory auditors routinely review gowning SOPs and observe actual gowning behavior to evaluate compliance. A failure to enforce overshoe use may be flagged as a GMP deviation under personnel hygiene, environmental control, or cleanroom contamination categories.

During inspections, regulators may request to review logs, gowning instructions, visual aids in gowning rooms, and training records. Observations of non-compliance often result in 483s (FDA), non-conformance reports (EU), or warning letters that question the adequacy of personnel training and the robustness of the gowning procedure. Facilities that fail to enforce overshoe usage may also be required to perform environmental root cause investigations in the case of repeated microbial excursions in Grade C areas. Maintaining a cleanroom’s classification depends on adhering to all elements of environmental and personal contamination control, with overshoes being a critical and often visible indicator of compliance discipline.

Implementation Best Practices

• Position overshoe dispensers at the entry point to Grade C gowning areas, along with disposal bins at exits.
• Train personnel thoroughly on gowning sequence, emphasizing overshoe donning before stepping into controlled zones.
• Use color-coded overshoes to indicate cleanroom zones and reduce cross-contamination.
• Include overshoe checks in routine GMP area audits and operator qualification programs.
• Document gowning violations and implement corrective training for repeated non-compliance.

Regulatory References

• FDA 21 CFR Part 211.28 – Personnel Responsibilities and Attire
• EU GMP Annex 1 – Manufacture of Sterile Medicinal Products
• WHO GMP – Section on Personnel Hygiene and Gowning
• Schedule M – Personnel Hygiene and Cleanroom Entry Protocols