Chicago mayor Rahm Emmanuel announced [press release, PDF] on Tuesday that his administration has filed a federal lawsuit [PDF] against the three largest distributors of opioid narcotics. The complaint names AmerisourceBergen Drug Corporation, Cardinal Health, and McKesson Corporation [corporate websites], companies that collectively account for about 90 percent of all prescription drug revenue in Chicago and are colloquially known as the “Big Three,” as defendants.

Attorneys for the city allege that the defendant’s distribution of opioids into Chicago has been “unfettered and unlawful,” further claiming that opioid prescriptions had tripled between 1999 and 2015. In that span, more than 183,000 Americans died from opioid overdoses, according to research by the Center for Disease Control cited in the complaint.

Defendants have a duty under federal and state law to exercise due diligence in order to prevent diversion and to monitor and report, and reject suspicious orders of controlled substances into the City. Such orders include, for example, orders of opioids that exceed reasonable volume, are of an unusual frequency, or that raise other red flags. Yet, Defendants shipped orders that they knew or should have known were being diverted or used other than for legitimate medical purposes. Sales and distribution data available to Defendants, as well as their own observations, would, or should, have put them on notice of potential diversion. Yet, upon information and belief, Defendants consistently failed to report or suspend these illicit orders, deepening the crisis of opioid abuse, addiction, and death in the City.

In addition to civil penalties, damages, and any other injunctive and equitable relief, attorneys for the city claim the primary purpose for the lawsuit is to hold the companies accountable for their contributions to the opioid epidemic.