FRESNO, Calif. (KFSN) -- Yosemite National Park's superintendent has announced his retirement amid complaints of a toxic work environment which could be part of a much bigger problem in the park service.Concerns of ugly actions in a beautiful place have forced the leader of Yosemite to say goodbye.In an email, Superintendent Don Neubacher said, "I regret leaving at this time but I want to do what's best for Yosemite National Park."Neubacher also said the National Park Service gave him two choices-- transfer to Denver or retire. It was an ultimatum to give Yosemite new leadership in light of complaints of bullying, discrimination and harassment. Neubacher chose retirement.According to a congressional oversight committee, 18 of the park's employees have come forward. They claim Neubacher created a horrific work environment by allowing misconduct to take place.One of the employees, Kelly Martin who is the Chief of Fire and Aviation Management testified last week, "I am here to tell you my story but more importantly to provide testimony regarding dark clouds of misconduct that remains elusive from public view."At Yosemite, Martin said she was humiliated and faced discrimination on the job. She also pointed to a larger problem of sexual harassment in the National Park Service. Martin described personal experiences outside of Yosemite and said there are other victims who choose not to speak, out of fear of retaliation."I did find my own way to push past these experiences and decided to preserve my opportunity for career advancement, my experiences would go unreported until now," Martin said during her testimony.As for Neubacher, prior to the retirement email, he issued an apology (also through email) to his employees and said, "it was never my intention, in any way, to offend any employee over the course of the six and a half years I have been superintendent."In that email, Neubacher also said, until recently, he wasn't aware of the concerns.Neubacher's official retirement date is November 1st. In the meantime, the National Park Service will continue to investigate the complaints.