The federal agency that oversees mental health and addiction treatment on Tuesday made major cuts to programs across the behavioral health field, according to eight sources with knowledge of the decisions.

While the exact funding cuts enacted by the Substance Abuse and Mental Health Services Administration remain unclear, the scope is clearly vast. Multiple sources told STAT that the number of overall grants canceled could number as high as 2,800, with the total dollars affected as high as $1.9 billion — over one-quarter of the agency’s overall budget. NPR first reported the cuts.

One high-level SAMHSA source told STAT that the agency’s staff were not aware of the cuts, which were not planned in consultation with agency staff or announced internally.

In letters informing grantee organizations of the funding cuts, SAMHSA said it was canceling grants to better align its spending with agency priorities, and informed recipient organizations that the decision was final. Documents reviewed by STAT showed that the cuts affect organizations providing a broad array of services, including comprehensive opioid treatment; addiction care for people experiencing homelessness; helping adults transition out of prison; HIV and hepatitis C prevention; and more.