President Donald Trump’s administration is talking tough about SNAP, saying the government’s biggest food aid program is riddled with fraud that must be stopped.

His appointees are looking at Supplemental Nutrition Assistance Program from an enforcement perspective, seeing fraud as a major and expensive problem, perpetrated by organized criminal organizations, individual recipients and retailers willing to break the laws for profit.

“We know there are instances of fraud committed by our friends and neighbors, but also transnational crime rings,” Jennifer Tiller, a senior advisor to U.S. Agriculture Secretary Brooke Rollins, said in an interview.

Some experts agree that SNAP fraud is a major problem. But there is little publicly available data showing the extent of it, and others who study the program are skeptical about the scale.

“It you’re spending $100 billion on anything, you’re going to have some leakage,” said Christopher Bosso, a professor of public policy and politics at Northeastern University who published a book on SNAP.

Of the $100 billion spent on SNAP a year, about $94 billion goes to benefits and the rest to administrative costs.

About 42 million people — or 1 in 8 Americans — receive SNAP benefits averaging about $190 per person per month. The number of recipients is in the same ballpark as the number of people in poverty — 36 million by the traditional measure and 43 million under a more nuanced one also used by the federal government.

Under federal law, most households must report their income and basic information every four to six months and be fully recertified for SNAP at least every 12 months.

The Trump administration has demanded that states turn over data on individual SNAP recipients including Social Security numbers, dates of birth and immigration status as part of its effort to root out fraud.

States with Republican governors, plus North Carolina, have complied. Most led by Democrats are pushing back in court, arguing that providing the data would violate recipients’ privacy.

The USDA says that from the records that have been shared, it found 186,000 deceased people — about 1% of participants in those states — receiving benefits and about 500,000 people — about 2.7% — receiving benefits in more than one jurisdiction.

The USDA has not made public detailed reports on the data and has not broken down the estimates by type of alleged fraud. The department also hasn’t answered questions about what portion of any improperly awarded benefits was actually spent and how much sat unclaimed on EBT cards after recipients moved or died.

The department estimated in a letter to the states that have refused to turn over data that the nationwide total combining fraud and undetected errors could be $9 billion a year or more. Democratic-led states responded in a letter last week that states already have systems to catch wrongdoing and that USDA isn’t explaining how it’s crunching the numbers.

There are a lot of forms of wrongdoing.

SNAP benefits are put on EBT cards that recipients swipe in stores like debit cards. Organized crime groups put skimmers on EBT readers to get information used to make copies of the benefit cards and steal the allotments of recipients — or to use stolen identity information to apply for benefits for fictitious people. A Romanian man who was in the U.S. illegally pleaded guilty last year to skimming cards in California. Authorities say he took more than 36,000 numbers over three years.

A USDA employee pleaded guilty this year to accepting bribes in exchange for providing registration numbers for EBT card readers placed illegally in several New York delis. Authorities said more than $30 million passed through those terminals.

And three people were charged this year in Franklin County, Ohio, accused of using stolen benefits to order big quantities of energy drinks and candy — apparently to resell it.

Mark Haskins, who worked on USDA investigations from 2013 until leaving the department in August as branch chief of a special investigations unit, said there have been cases of retailers running similar operations. Several states are barring using SNAP for some junk food products with policies that kick in as soon as Jan. 1.

Haskins also says some legitimate recipients buy non-grocery items with SNAP benefits by persuading a store employee to ring up the wrong item — generally one that costs more than what’s being bought — or to sell benefit cards. He said he thinks those forms of fraud are more costly than the ones run by organized criminal groups.