From the Document: "Immigration law in the United States has long contained exclusion and removal provisions designed to limit government spending on indigent non-U.S. nationals. (Non-U.S. nationals are referred to as 'aliens' in immigration law.) Under the Immigration and Nationality Act (INA), an alien may be denied admission into the United States or lawful permanent resident (LPR) status if he or she is 'likely at any time to become a public charge' (8 U.S.C. §1182(a)(4)). An admitted alien may also be subject to removal from the United States based on a separate public charge ground of deportability, but this is rarely employed. The Department of Homeland Security (DHS) and the Department of State (DOS) have primary responsibility for implementing the public charge ground of inadmissibility. DHS makes public charge inadmissibility determinations for aliens seeking admission or 'adjustment' from a temporary status to LPR status. DOS consular officers make public charge inadmissibility determinations for aliens abroad applying for U.S. visas, based on guidance in the Foreign Affairs Manual (FAM). While this applies to both immigrant and nonimmigrant (i.e.,temporary) visas, in practice it is rarely employed for nonimmigrant visas. Certain categories of aliens, such as refugees and asylees, are exempted from the public charge ground of inadmissibility. It is not applicable to aliens who are applying for citizenship (i.e., naturalization)."
CRS In Focus, IF11467
Congressional Research Service: https://crsreports.congress.gov/