A National Institutes of Health scientist is retiring after 21 years on the job, blaming changes made under Health and Human Services Secretary Robert F. Kennedy Jr.

Kevin Hall, who specialized in nutrition and metabolism for the institute, is the latest to leave the department since Kennedy laid off large swaths of employees. While most layoffs were done in the name of cost savings, Hall is alleging that changes to the agency “made me question whether NIH continues to be a place where I can freely conduct unbiased science.”