HARTFORD, Conn. — Middle school-aged students from Connecticut on a field trip last year were forced to re-enact slavery by pretending to be sold at auction and in fields picking cotton, according to a student’s complaint. They were told they would be whipped or worse if they ran, and some were asked to dance for their masters.

“I had to hold my head down and could not make contact with the white masters,” the 12-year-old student, who is black, said in a statement read to the Hartford school board this week by her father, James Baker of suburban Farmington. “I heard the instructor ask kids behind me to open their mouths so their teeth could be checked. Some were asked to jump up and down.”

The girl, who was a seventh-grader at the Hartford Magnet Trinity College Academy, asserts that she and her classmates were traumatized and subjected to racial epithets during the November field trip to the Nature’s Classroom, an environmental-based outdoor education program in Charlton, Mass., about 45 miles from Hartford. The family has filed a complaint against the school district.

In addition to pretending to be sold at auction and picking cotton, the students participated as slaves in a re-enactment of the Underground Railroad and simulated being on slave ships.

Instructors, acting as the oppressors, told them that while on the ship they would be forced to go to the bathroom on each other and would be thrown overboard if they got sick, the girl said.

“I went into a dark room where I had to sit on my bottom with my knees together,” she said in the statement. “My legs fell asleep and were hurting.”

Jon Santos, the director of Nature’s Classroom, defended the three-hour simulation Friday as an empathy-building activity that helps teach students about slavery, and also has lessons about modern issues such as bullying. He said the activity, which is not supposed to involve racial epithets, has been part of the program for about 18 years, he said.

“This is a re-enactment of a historical event that has relevance to their day-to-day interaction with their peers and classroom teacher,” he said. “How do you feel when this is put upon you? How do you think you should feel when it is put upon someone else?”

The complaint was filed with the state Commission on Human Rights and Opportunities in March and led to a meeting in August between program officials and the state Department of Education.

A spokesman for the Hartford school district, David Medina, said Friday he could not comment on a pending case before the commission. Sally Biggs, principal of Hartford Magnet Trinity College Academy, did not return a phone message seeking comment.

Glenn Cassis, the director of the state’s African-American Affairs Commission, said he notified lawmakers and expects them to open their own inquiry of the program, which he said several Connecticut schools attended.

“Kids don’t process that in a way where they know this is just a play or an act or something,” he said. “This is not the way to teach them about this.”

Program officials failed to adequately brief parents about the simulation, a report from the Department of Education said, and the program also lacked key components, such as a statement of clear objectives and instructions to staff, and a way to gauge students’ ability to emotionally handle the content.

“Playing the role of an oppressed person or oppressor can be traumatic and reinforce negative stereotypes,” the report said.

Santos said he never received a complaint at the time of the field trip and would have fired anyone who used the racial slur.

He said the program is being changed and will include clearly defined goals and objectives. He also stressed that it is one of dozens of activities offered to schools, which volunteer to participate.

“There are real feelings that we are eliciting,” he said. “Is it appropriate? That’s up for debate. I wouldn’t deny that. This isn’t pushed upon anyone. A person could opt out.”