Wisconsin transgender teenager Ash Whitaker recently made national headlines for winning his right to run for prom king. Now he’s fighting another battle with the Kenosha Unified School District.

Whitaker is still fighting for his right to use the bathroom that matches his gender identity, Transgender Law Center officials announced Wednesday. The Kenosha News reported that Whitaker had been followed by school security when he went to the bathroom and had been asked to use the staff bathroom in the school office.

The center said it sent a letter to the school district this week demanding transgender students be allowed to use facilities that match their gender identity, or face legal consequences for violating federal law.

In a MoveOn.org petition that boasted more than 7,560 signatures as of Friday, Whitaker said his prom king victory represents a half-completed battle.

“My school still refuses to respect and acknowledge my gender identity in respect to restroom usage. Please sign this petition and help support my cause!” Whitaker said.

The Transgender Law Center said Wednesday that Whitaker had used the boys’ restrooms without problems or protest since the beginning of the school year, “until school administrators intervened and threatened him with disciplinary action.”

In the letter to the district, the Transgender Law Center added the school this month changed the locks to two single-use campus restrooms and gave Whitaker exclusive access to those bathrooms.

The restrooms had been open to the public. Whitaker said he has avoided using the restrooms to escape embarrassment from using bathrooms different than his peers.

Jill Marcellus, a spokesperson for Transgender Law Center, told Rewire that the restroom situation at Tremper High School is an ongoing issue and that the legal center is representing Whitaker.

“It’s the first action the student is taking to really change what the district is doing,” Marcellus said.

Whitaker said in a statement that the school was no longer a safe, welcoming place for him.

“Being banned from the boys’ bathroom is a daily reminder that school administrators see me as someone who is so different from the other students that I’m not even allowed to share a bathroom with them,” Whitaker said.

The center has noted that the U.S. Department of Education’s Office for Civil Rights, which enforces Title IX of the U.S. Education Amendments of 1972, has interpreted Title IX to require schools to allow transgender students to use facilities consistent with their gender identity.

A Kenosha Unified School District spokesperson was not available for comment.