A Michigan state lawmaker apologized on Tuesday after attempting to bring an unregistered, loaded gun on a plane last month.

State Rep. Lee Chatfield (R), who serves as speaker pro tempore of the Michigan House of Representative, issued the apology in a Facebook post, saying it was an “inexcusable mistake.” 

“As an elected official, I take responsibility and fully acknowledge that no one is above the law,” Chatfield said. “I am sorry for this honest mistake, and I can ensure you that it won’t happen again.”

The Detroit Free Press reported that Chatfield’s apology stemmed from an incident at the Pellston Regional Airport on July 15, when TSA found a loaded, unregistered handgun in his carry-on bag during a pre-flight screening on his way to Detroit.

Chatfield was detained by a deputy and questioned at an Emmet County Sheriff’s Office substation, according to the Petoskey News-Review. He was not arrested because the incident didn’t result in any imminent danger, The Free Press reported. His gun was confiscated.

In his Facebook post, Chatfield said he owns several firearms and that he thought all were registered with Michigan State Police. The one in his carry-on, however, was not. Chatfield said he has since gotten the firearm registered.

The Free Press notes that Chatfield’s case is in the hands of Emmet County Prosecuting Attorney’s Office. The office is currently determining  if any charges will be filed.