As the number of personal exposure studies expands and trends favor greater openness and transparency in the health sciences, ethical issues arise around reporting back individual results for contaminants without clear health guidelines. Past research demonstrates that research participants want their results even when the health implications are not known. The experiences of researchers and institutional review boards (IRBs) in studies that have reported personal chemical exposures can provide insights about ethical and practical approaches while also revealing areas of continued uncertainty. We conducted semi-structured interviews with 17 researchers and nine IRB members from seven personal exposure studies across the United States to investigate their experiences and attitudes about the report-back process. Researchers reported multiple benefits of report-back, including increasing retention and recruitment, advancing environmental health literacy, empowering study participants to take actions to reduce exposures, encouraging shifts in government and industry practices, and helping researchers discover sources of exposure through participant consultation. Researchers also reported challenges, including maintaining ongoing contact with participants, adopting protocols for notification of high exposures to chemicals without health guidelines, developing meaningful report-back materials, and resource limitations. IRB members reported concern for potential harm to participants, such as anxiety about personal results and counterproductive behavior changes. In contrast, researchers who have conducted personal report-back in their studies said that participants did not appear overly alarmed and noted that worry can be a positive outcome to motivate action to reduce harmful exposures. While key concerns raised during the early days of report-back have been substantially resolved for scientists with report-back experience, areas of uncertainty remain. These include ethical tensions surrounding the responsibility of researchers to leverage study results and resources to assist participants in policy or community-level actions to reduce chemical exposures, and how to navigate report-back to vulnerable populations.