The Los Angeles Memorial Coliseum Commission and the event company Insomniac were sued Thursday by the parents of a teenage girl who died of an Ecstasy overdose after attending a rave at the stadium.

The suit also names former Coliseum events manager Todd DeStefano, whom Insomniac employed as a consultant while he held the stadium job, and two private companies he formed. Those companies received at least $1.8 million in payments from firms that also did business with the Coliseum.

The suit alleges that the defendants were negligent in their supervision of the Electric Daisy Carnival concert in June 2010.

Sasha Rodriguez took Ecstasy, an illegal drug, after entering the venue, the lawsuit says, and overcrowded and understaffed conditions “delayed the response of on-site security and emergency medical services providers to her by approximately 20 minutes.” The suit also describes the security and medical workers as “inadequately trained.”

By the time Rodriguez arrived at a hospital, “she was non-verbal with saliva bubbling at the corners of her mouth,” the suit says. “Shortly after arriving at the emergency room she suffered a seizure.”

The Coliseum, Insomniac and DeStefano should have known that the rave would “enable widespread illegal and illicit activity which endangered the health, safety and well-being of all” attendees, including Rodriguez, according to the lawsuit, which was filed in L.A. County Superior Court.

The plaintiffs seek punitive damages against Insomniac “to set an example ... and to dissuade it from future reckless and illegal conduct.”

The suit accuses Insomniac and DeStefano of conspiring to increase the rave’s attendance “beyond a reasonable capacity” and adds, “DeStefano’s divided loyalties played a crucial part in Insomniac’s inadequate security and emergency medical services preparations.”

Donovan Main, a commission attorney, said the commission had not yet received the lawsuit, and he had no comment.

A lawyer for DeStefano did not respond to a request for comment. Gary Jay Kaufman, a lawyer for Insomniac, issued a statement that called the case “completely without merit.

“ .While Ms. Rodriguez’s death is an unspeakable tragedy, the complaint fully admits that she knowingly ingested an illegal drug,” the statement said. " As will become clear when all the facts are known, she made personal choices that we cannot control.”

ron.lin@latimes.com

andrew.blankstein@latimes.com