The Drug Enforcement Administration skirted numerous legal checks on a trio of bulk data collection programs dating back to the early 1990s, according to an internal watchdog.

In a heavily redacted, 144-page report published Thursday, the Justice Department Inspector General revealed the administration failed to fully assess the legal basis for three massive international surveillance operations that ran largely unchecked from 1992 to 2013. Two of the programs remain active in some form today.

Under one initiative, which investigators called "Program A," the administration used "non-target specific" subpoenas to force multiple telecom providers to provide metadata on every phone call made from the U.S. to as many as 116 countries with "a nexus to drugs." Investigators found some companies also provided the officials with data on all calls made between those foreign countries.

The administration also conducted two other bulk surveillance programs during that time without assessing their legality, investigators found. Under "Program B," officials used similarly sweeping subpoenas to collect information on anyone who purchased specific products from participating vendors. Through "Program C," DEA purchased telephone metadata for targets of ongoing investigations through a contractor for a separate government agency.