It is possible to wear ESD & Cleanroom apparel over regular clothing, but it is not always recommended. Wearing additional layers under the ESD & Cleanroom apparel may affect the fit and reduce the effectiveness of the clothing in protecting against electrostatic discharge and particulate contamination.
In a cleanroom environment, it is important to wear only the designated cleanroom attire to avoid introducing contaminants from outside clothing. In an ESD-sensitive environment, wearing additional layers can also increase the risk of generating static electricity and causing electrostatic discharge.