A practice used to prevent personnel contamination while working in contamination areas is to:

Using a blotter to cover a contaminated surface, such as the floor, when kneeling is an effective practice to prevent personnel contamination in areas where there is a risk of radioactive material. By providing a barrier between the contaminated surface and the individual's clothing or skin, this method significantly reduces the possibility of contamination being transferred to the worker. This is especially important, as contamination can lead to internal exposure if radionuclides adhere to clothing and are later ingested or inhaled.

This practice emphasizes the importance of maintaining good contamination control measures, which are crucial in radiological work environments. It helps to ensure that personnel can perform their tasks safely while minimizing the risk of spreading contamination, hence protecting both the worker and the integrity of the work area.

Other practices mentioned could potentially expose personnel to contamination or are less effective in managing contamination risks. For example, applying duct tape to facial areas does not effectively address contamination exposure and might create additional safety hazards. Additionally, ensuring hoses, lines, and cables are not taped down prevents trip hazards but does not inherently prevent contamination. Lastly, making multiple entries to complete a single task can unnecessarily increase the risk of contamination by exposing personnel to high-risk areas repeatedly.