Which of the following is considered a "one and done" sign of unauthorized deleading?

A "one and done" sign of unauthorized deleading refers to an immediate indication of a significant issue with lead abatement, particularly where the results show contrasting conditions. In this context, when the door edge is negative but both faces are positive, it suggests that the deleading procedure may have been improperly completed. This means that while one side of the door has tested negative for lead, which is expected after proper remediation, the other sides testing positive indicate that lead has not been fully addressed.

This situation signifies a clear failure in the deleading process, showing that lead hazards remain. Proper deleading should result in consistent negative results across all areas, especially on surfaces typically subject to exposure.

The other options do not represent the same level of immediate indicator. Leaded window sills may signify risk but do not confirm whether unauthorized deleading occurred specifically. Positive lead tests in all rooms indicate a hazardous environment but do not single out an inadequate remediation action. Multiple documented inspections may highlight ongoing issues or concerns but are not an immediate sign of unauthorized deleading on their own. Therefore, the door edge condition serves as a strong indicator of improper or unauthorized deleading actions.