Lehigh County Executive William H. Hansell resigned from his post May 17 citing health concerns.

Hansell was appointed last summer to fill the unexpired term of Don Cunningham.

Recently hospitalized with pneumonia Hansell was diagnosed with non-Hodgkins lymphoma.

He is undergoing treatment and, said in a press release, he must devote his energy to combating his illness.

"I have been proud to serve as Lehigh County executive for the past year," Hansell stated in his letter of resignation. "I felt it was the culmination of my 52-year career in local government.

"The decision to resign has been one of the hardest I've had to make in my professional life."

Lehigh County Director of Administration Thomas Muller has been appointed acting executive.

"I have every confidence in Tom's ability to carry out the responsibilities of this position and to serve all the residents of Lehigh County," Hansell said in his statement.