Aby Mohseni, acting head of high-level waste repository safety, says in prepared testimony for a House hearing Friday that Nuclear Regulatory Commission chairman Gregory Jaczko and other officials have allowed politics to influence the staff's scientific work.
Mohseni's comments are the most scathing to come from inside the agency. Other scientists had objected earlier to Jaczko's decisions.
Jaczko ordered Mohseni's unit to stop its review of the dump in October.
A recent inspector general's report found that Jaczko acted within his authority, but did not fully inform other commissioners of his plans.