Washington Attorney General Bob Ferguson announced Tuesday he will sue the three largest opioid distributors in the state to hold them accountable for "the harm that they have caused."

Ferguson alleges that McKesson Corporation, Cardinal Health, and AmerisourceBergen Drug Corporation continued to ship suspicious orders to Washington, despite a legal obligation to stop those shipments and report them to federal drug authorities. 

An order is considered suspicious based on specific factors, such as a pharmacy tripling its orders or going from one order a month to one order a week over a short period of time, according to Ferguson.

“These three companies had a legal obligation to be a key line of defense against the free flow of opioids into our state," Ferguson said. "Instead they were driven by greed.”

WATCH: Ferguson announced lawsuit against drugmakers

Those three companies supplied over 2 billion opioid pills to Washington between 2006-2014, according to Ferguson.

Depending on how conservative the calculation, the lawsuit claims those three companies shipped between 250,000 and nearly 1 million suspicious orders over that same time period. Ferguson argued that influx of pills led to more prescriptions filled, more pills on the black market, and more addiction.

If internal monitoring flagged an order as suspicious, the suit claims the three companies shipped it anyway.

“We’ve seen the data, and it is shocking," Ferguson said. "The opioid epidemic has devastated Washington state families and wreaked havoc on our health system, all because these pills were flooded into the state in astonishing numbers.”

Ferguson announced the suit alongside Quinault Indian Nation President Fawn Sharp, Washington State Department of Labor and Industries Medical Director Dr. Gary Franklin, and several mothers impacted by the epidemic.

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Several Washington cities and counties have already filed lawsuits against drugmakers aiming to hold them responsible for the illegal diversion of drugs onto the black market. Snohomish County was the latest to file a suit against Purdue Pharma in January; others include Kitsap, Skagit, and Whatcom counties.