The city once had an aggressive overdose prevention strategy, but as officials became preoccupied with other crises, many of their efforts stalled.

Reporters for The Banner teamed up with The Times’s Local Investigations Fellowship, which gives local journalists a year to pursue an investigative story about their communities. They reviewed thousands of pages of government documents and interviewed more than 100 health officials, treatment providers and people who have been addicted to drugs to examine the city’s response.