43 Northwest Chipotle' restaurants in the Pacific Northwest are set to re-open as early as next week, after Washington State Department of Health officials did not find a definitive source for the e-coli outbreak that sickened at least 40 people.

The illness was largely confined to a four county area around Seattle, and two in Oregon. At least 40 people were confirmed to have contracted the virus, which causes severe intestinal disorders and health issues.

As a precaution, the chain's 43 stores in Oregon and Washington were closed voluntarily by the chain during the investigation. This included the one in Tri-Cities.

Two lawsuits have been filed over this outbreak, and earlier this year in August, several dozen people were sickened by a salmonella outbreak linked to tomatoes at Chipotle' outlets in Minnesota.  Norovirus linked to food at a Chipotle' in Simi Valley, CA sickened about 100 people in mid-August.

Seattle attorney Bill Marler, who has filed the two lawsuits against the restaurant, claims the chain has been the subject of food safety issues. He says just because the Oregon and Washington state health departments have not been able to pinpoint the source of the e-coli doesn't mean they don't hold the company responsible.

Health department officials said although many food-related illness outbreaks can eventually be traced, it's usually like trying to find a needle in a haystack, and often the sources of contamination are never found.