The online sale from Chinese labs of the synthetic opioid fentanyl, the top driver behind the unprecedented overdose deaths in the United States deemed a top national security threat, reached nearly $800 million over two years, reveals a newly unveiled Senate investigation.

During a hearing Thursday focused on the report authored by the Senate Homeland Security and Government Reform Subcommittee on Investigations, the panel’s Chairman Rob Portman (R-OH) revealed in his prepared remarks:

It is not surprising that people are ordering fentanyl online to sell; the profit margins are staggering. Based on DEA estimates, the street value of the online transactions from just the six websites the Subcommittee investigated translates to around $766 million in fentanyl pills to sell on the streets of our communities.

The U.S. government has determined that China is “the primary source of fentanyl in the United States.”

Senate investigators explained that their report entailed a year-long probe into just six websites affiliated with Chinese labs.

They found that most consumers reside in Ohio, Pennsylvania, New York, and Florida, among the states with the highest number of overdoses.

“Just from these six websites, we identified more than 500 payments to online sellers by more than 300 Americans totaling $230,000, most of which occurred over the last two years,” noted Sen. Portman. “These 300 people were located in 43 states, with individuals in my home state of Ohio, Pennsylvania, and Florida sending the most money to the online sellers.”

Chinese sellers prefer Bitcoin, the digital currency, as a form of payment and choose to ship the drugs via other countries to reduce detection, noted the report.

The report also found that the online sellers preferred to use the U.S. Postal Service over private services such as FedEx and UPS because the postal service only receives advance electronic information on “about 36 percent” of the millions of international packages coming into the U.S., making it easier to exploit.

“This is a massive loophole that is undermining the safety and security of our country,” Portman said, adding, “They told us they used the Postal Service because the chances of the drugs getting seized were so insignificant that delivery was essentially guaranteed. “

In 2016, doctors dubbed Cuyahoga County, Ohio, the nation’s opioid overdose capital.

Dr. Thomas Gilson, the chief medical examiner for Cuyahoga County, told U.S. lawmakers last May that coroner’s offices across the United States are facing “personnel shortages” and equipment failures due to the high number of overdose fatalities, fueled primarily by fentanyl.

“In my home state of Ohio, fentanyl and its variations were involved in almost 60 percent of all overdose deaths in 2016,” declared Chairman Portman.

Synthetic opioids such as Fentanyl are the top driver (20,145 fatalities) behind the unprecedented 64,070 drug overdose deaths last year, according to the U.S. Centers for Disease Control and Prevention (CDC).

Taken together—all opioids, including natural, synthetic, semi-synthetic, and methadone—were responsible for the majority (83 percent) of fatal overdoses, prompting U.S President Donald Trump’s administration to declare a public health emergency, which means the government is expected to devote more resources to combating it.

The number of people killed by synthetic and natural opioids in the United States alone last year far exceeded those murdered by terrorists across the world, Breitbart News has determined using CDC and U.S. State Department data.

Trump’s congressionally-mandated National Security Strategy (NSS) deemed Latin American drug cartels who smuggle heroin and Chinese traffickers of the synthetic opioid fentanyl a threat to the United States for killing “tens of thousands of Americans each year.”

The administration listed fentanyl traffickers as threats to Americans alongside jihadist groups and rival nations.