Industrial hygienists are uniquely situated to help solve problems in the working environment, and failure to behave ethically might have serious and possibly fatal consequences. A survey was conducted to estimate the prevalence and nature of ethical misconduct within the UK occupational hygiene profession during the past 5 years. A postal questionnaire was sent to 50 professional industrial/occupational hygienists. Of the 43 respondents, 33 (77%) had witnessed activities of potential ethical misconduct in at least one of nine questionnaire categories. Additionally, greater than 20% of the hygienists had witnessed at least one incident of data fabrication, failure to share credit on work, failure to protect confidentiality, criticizing the integrity of another hygienist for one's own gain, and plagiarism. The investigation also asked hygienists for their opinions on the reasons for breaches as well as potential methods of improvement.