What type of data would be least useful in understanding the environmental impact of a chemical?

The least useful type of data in understanding the environmental impact of a chemical would be results from promotional campaigns. This is because promotional campaigns are typically designed to highlight the positive aspects and benefits of a chemical or product, often aiming to persuade the public or stakeholders of its safety or value. They may not provide accurate or comprehensive information regarding potential environmental impacts, risks, or harmful effects associated with the chemical.

On the other hand, scientific research findings offer rigorous, peer-reviewed insights into the chemical's behaviors, interactions, and effects on ecosystems, making them crucial for understanding environmental impacts. Governmental regulations regarding chemical use provide important context about safety standards, permissible levels, and necessary precautions, which directly relate to environmental management and protection. Environmental impact assessments systematically evaluate the effects a chemical may have on the environment, thus providing essential data that informs decision-making processes aimed at minimizing harm.