Senate Democratic tax writers are demanding more details about former Rep. Billy Long’s work promoting a troubled pandemic era tax credit for businesses as they consider his possible nomination to head the IRS.

In a pair of letters to companies Long (R-Mo.) said he worked with, the lawmakers want to know how much money he made promoting the Employee Retention Credit, how many claims they filed, whether any clients ended up getting audited and if any applications were deemed improper or fraudulent, among other things.

The letters released Wednesday mark the beginning of what Democrats say will be close scrutiny of Long’s promotion of the fraud-plagued credit after he left Congress last year. President-elect Donald Trump named Long, a loyalist, to replace IRS Commissioner Danny Werfel, though Werfel is only midway through his five-year term.

“Long’s work peddling ERTC claims is deeply concerning in light of the industry level of fraud that has taken place across the scam-plagued ERTC industry,” wrote Senate Finance Chair Ron Wyden (D-Ore.) and Sen. Catherine Cortez Masto (D-Nev.) to Commerce Terrace Consulting.

“This information will help senators better understand Mr. Long’s fitness to oversee tax administration and the enforcement of federal tax laws.”

They sent a similar letter to a company called Lifetime Advisors.

The IRS has been battling a torrent of suspicious filings retroactively seeking the lucrative credit, which was offered during the pandemic to help prevent layoffs. But in a podcast last year, Long said “virtually everyone” qualifies for the credit, and told listeners to ignore accountants who said they were ineligible.

Long bragged about getting clients seven-figure payments.

Neither Wyden nor incoming Finance Chair Mike Crapo (R-Idaho) have met with Long since Trump tapped him for the IRS post, less than two months before the next tax-filing season will begin.