Two business immigration groups have filed a lawsuit seeking information about how the H-1B visa distribution system — including the visa lottery — works. It alleges that the U.S. has no right to keep most of the records secret.

It is not surprising that the H-1B distribution system is coming under scrutiny in a lawsuit. The U.S. Citizenship and Immigration Service (USCIS) this year received 236,000 H-1B visa petitions for the 85,000 visas allowed under the current cap. The agency distributes visas each year via a lottery. The odds — roughly one-in-three — create a lot of frustration for applicants.

The H-1B lottery uses a “computer-generated random selection process,” according to the U.S. government. But officials have not disclosed exactly how that process works, identified the software vendor nor said who is responsible for maintaining the code.

The lawsuit filed in federal court by the American Immigration Lawyers Association (AILA) and the American Immigration Council (AIC) doesn’t allege any specific wrongdoing. But it does argue that the process used to the distribute visas ought to be open to inspection.

“I think the government should be transparent about what it does in the immigration area,” said Melissa Crow, the legal director of the AIC. “This is one big black hole.”

In November 2014, Crow said AIC filed a Freedom of Information Act Request for information; in response, the U.S. government provided some 521 pages of records. But only 166 pages “were released in their entirety.” The remaining records were either “withheld in full” or “heavily redacted,” according to the lawsuit.

“There were many emails with tantalizing hints of what we were not receiving, such as guidance to USCIS’s contractor on the rejection process,” Leslie Dellon, a business litigation fellow at the AIC, wrote in a note summarizing the disclosure.

“It’s disturbing that these plans were withheld under the exemption for ‘trade secrets and commercial or financial information obtained from a person and privileged or confidential,'” wrote Dellon. “Administering the lottery is a governmental function.”

The lawsuit, filed May 20, seeks records that explain the process for handling H-1B visas subject to the current cap. That includes explaining the reasons why a visa petition might be rejected upon receipt and not included in the lottery. It also wants to know how the USCIS determines when it has received petitions to reach the 65,000 base cap and the separate 20,000 master’s degree cap.

It also wants to know “how the random selection process is conducted.”

USCIS officials were not immediately available for comment on Monday about the lawsuit.

Crow said the AIC has reached no conclusions about how the H-1B visa distribution system works, and will wait until officials see what the records reveal.

Separately, President Barack Obama’s administration has begun making a case for third-party audits of decision-making algorithms. Because of the importance of these systems, they may need to be transparent for testing and auditing, it said in a recent paper.