Medical supervision from a doctor is required if employees regularly handle organophosphate pesticides with:

Medical supervision from a doctor is mandated when employees regularly handle organophosphate pesticides that carry the signal words "WARNING" or "DANGER." These signal words indicate a higher level of toxicity and risk associated with the pesticide, suggesting that there is potential for significant health effects if proper precautions are not taken.

Organophosphate pesticides are known to affect the nervous system, and the risk of exposure increases with the severity of the toxicity indicated by these signal words. "WARNING" suggests moderate toxicity, while "DANGER" signifies high toxicity, fundamentally requiring increased levels of safety measures, such as medical oversight, to safeguard the health of employees who are consistently engaged in the handling of these substances.

On the other hand, signal words like "CAUTION" indicate lower toxicity, which may not require the same level of medical supervision. Labels with no signal words or simply any label present do not necessarily reflect the serious health risks associated with organophosphate pesticides. Thus, the presence of the specified signal words is critical in determining the need for medical supervision in relation to pesticide handling.