When 28 Wisconsin counties sued several pharmaceutical companies last week, they became among the latest government entities in a wave of litigation accusing the industry of contributing to the prescription opioid and heroin addiction epidemic gripping the country.

From California to New Hampshire, dozens of lawsuits in federal, state and county courts are alleging that Big Pharma inundated the country with painkillers by deceiving doctors and the public about their safety. Many of the cases were brought by plaintiffs lawyers who have teamed up with governments to sue the companies through contingency-fee agreements.