Alphabet Inc’s <GOOGL.O> Google is teaming up with a health-care company on a secret project to collect personal health-related information of millions of Americans across 21 states, the Wall Street Journal reported on Monday.

Google launched “Project Nightingale” last year with St. Louis-based Ascension, according to the report, citing people familiar with the matter and internal documents. (https://on.wsj.com/2q3WCer)

Google and Ascension did not immediately respond to a Reuters request for comment.

The data involved in Project Nightingale includes lab results, doctor diagnoses and hospitalization records, among other categories, and amounts to a complete health history, complete with patient names and dates of birth, the Journal reported.

The news follows an earlier announcement from Google that it would buy Fitbit Inc <FIT.N> for $2.1 billion, aiming to enter wearables segment and invest in digital health.