ST. LOUIS—Excess workers compensation insurer Safety National Casualty Corp. said Chief Executive Officer Terrence Schoeninger will retire effective Jan. 1, 2010.

Mark Wilhelm, president and chief underwriting officer, will become CEO while Mr. Schoeninger will remain on the company’s board of directors, Safety National said Thursday.

Additionally, Gerald Scott, chief operating officer, will become president. Duane Hercules, chief financial officer, will become COO.

All the changes are effective Jan. 1, 2010, according to the St. Louis-based unit of Delphi Financial Group Inc. that also provides an array of alternative risk funding products.

“Terry Schoeninger has played a critical role in the growth of Safety National over his 30-year tenure with the company,” Mr. Wilhelm said in a statement. “The Safety National management team has worked together for 25 years, and we are confident that the succession of existing members of that team to their new roles will continue the consistent and excellent leadership that has built this company into what it is today.”