At a private meeting in September, congressional aides asked Rebeckah Adcock, a top official at the Department of Agriculture, to reveal the identities of the people serving on the deregulation team she leads at the agency.

Teams like Adcock’s, created under an executive order by President Trump, had been taking heat from Democratic lawmakers over their secrecy. What little was publicly known suggested that some of the groups’ members had deep ties to the industries being regulated.

Adcock, a former pesticide industry executive, brushed off the request, according to House aides familiar with the exchange, who asked for anonymity because they were not authorized to comment publicly. Making the names public, they recalled her saying, would trigger a deluge of lobbyists.

In fact, interviews and visitor logs at the Agriculture Department showed that Adcock had already been meeting with lobbyists, including those from her former employer, the pesticide industry’s main trade group, CropLife America, and its members. CropLife pushes the agenda of pesticide makers in Washington, including easing rules related to safety standards and clean water.

Adcock, who left the trade group in April, maintained contact with her former industry allies despite a signed ethics agreement promising to avoid for one year issues involving CropLife as well as matters that she had lobbied about in the two years before joining the government.

In one meeting, Adcock discussed issues banned by the ethics agreement with an executive who had been her lobbying partner weeks earlier at CropLife, according to the accounts of participants and the visitor logs, obtained through a public records request by The New York Times and ProPublica.

Tim Murtaugh, a spokesman for the USDA who also spoke on behalf of Adcock, said she had not violated her ethics agreement by meeting with her former industry allies. He also denied that Adcock had discussed issues related to her previous lobbying at the meeting, or that she had suggested that her deregulation team would be swamped by lobbyists if names of its members were released.

“The career ethics officers at USDA agree that this is not a violation of the ethics agreement that Rebeckah Adcock signed,” said Murtaugh, citing a 2009 memo by the Office of Government Ethics.

Others dispute that interpretation of the memo; the ethics office declined to say whether the memo applied to the meeting, citing its policy not to discuss individual cases.

Adcock is scheduled to appear Tuesday before subcommittees of the House Committee on Oversight and Government Reform, which is tracking Trump’s deregulation effort. In announcing the hearing, the committee, led by Republicans, applauded the deregulation teams for making an “unprecedented reduction in the federal regulatory footprint.”

Republican members of the committee declined to comment about Adcock’s activities. Representative Elijah E. Cummings, the top Democrat on the committee, said that if Adcock had violated her ethics agreement, it contributed “to a troubling pattern of President Trump’s failure to ‘drain the swamp.”

In February, Trump ordered major federal agencies to set up the deregulation teams, to fulfill a campaign promise to cut red tape for businesses. Corporations and industry groups quickly hired lawyers, lobbyists and economists to help them influence the process with billions of dollars at stake. The regulations under review cover a range of subjects, including the cleanliness of drinking water and the safety of highways.

The Trump administration has declined to make public the names of many members of the teams. It has also generally not provided records related to the teams’ calendars and correspondence.

A joint investigation published in July by The Times and ProPublica found that the teams included former employees of industry-financed organizations that oppose environmental regulations; lawyers who have represented companies in cases against federal regulators; and staff members of so-called political dark-money groups. Some are reviewing rules that their previous employers sought to weaken or kill, and at least two may be positioned to profit personally if certain regulations are undone. In all, the two news organizations have identified 112 current and former team members, including 41 with potential conflicts.

At the meeting on Capitol Hill in September, Adcock lamented the scrutiny that her team was under, a House aide familiar with the exchange said. Adcock cited, in particular, public records requests for calendars and emails.

The Times and ProPublica asked for those records this year and have received only a few. Most other federal agencies have been similarly unresponsive. The visitor logs that have been obtained are often handwritten sign-in sheets. They appear to show only a fraction of meetings, and many are illegible. It is not known from the logs, for example, if Adcock or her team had met with environmental or science groups in addition to the industry representatives.

In response to questions from reporters about possible conflicts of interest, agency officials across the government have said the deregulation teams are abiding by strict ethical standards, including rules that bar them from working on issues directly affecting recent employers.

Records received through a Freedom of Information Act request show that Adcock entered such an agreement on April 26, pledging that she would “not participate personally and substantially in any particular matter involving specific parties in which I know CropLife America is a party or represents a party” for a year.

But in May, Kellie Bray, a lobbyist for CropLife, arrived for a meeting with Adcock, according to the visitor logs.

The two knew each other well. From 2010 to early this year, Adcock and Bray lobbied together for CropLife, which represents Syngenta and Monsanto, among other pesticide makers.

Disclosure records show that during those years the two advocated for the industry’s agenda at agencies, including the USDA and the Environmental Protection Agency, and in Congress. They pushed CropLife’s interests on bills and regulations relating to the impact of pesticides on water and human health.

Adcock’s departure from CropLife left the trade association short a seasoned lobbyist, but gave it a valuable contact in the top ranks of the USDA

Bray said in an interview that in May, Adcock had met with her and the Southern Crop Production Association, a CropLife affiliate. Bray said she had sat in on the meeting but hadn’t talked.

“I facilitated the introduction,” she said. “That is all.”

After the meeting, the Southern Crop Production Association, which represents pesticide manufacturers, formulators and distributors across the South, said on its website that “Rebeckah has an exceptional understanding regarding the many issues facing agriculture due, in large part, to her previous position with CLA,” using the acronym for CropLife America.

Among the topics discussed, according to the trade group’s website, were the tests that pesticides must undergo to prove they are safe and rules governing their use near water sources. The trade group did not respond to requests for comment. Bray confirmed that the group had discussed regulations about the use of pesticides near water.

Discussing policy related to the impact of pesticides on water is deemed off limits under Adcock’s ethics agreement. Murtaugh, the USDA spokesman, said Adcock disputed that she had discussed any off-limits subject.

“If any participant declared concern regarding any issue precluded by Adcock’s agreement, she politely and firmly instructed them it was not a matter she could discuss or assist with,” he said.

He also said Adcock had instructed Bray not to participate in the meeting and did not recall her being in the room.

Murtaugh said a provision in the memorandum from the Office of Government Ethics allowed an appointee like Adcock to attend meetings with a former employer or client so long as five or more other stakeholders participated. In the May meeting, he said, four of the Southern Crop Production Association representatives were affiliated with individual companies: Syngenta, Albaugh, Triangle Chemical and Crop Production Services.

However, three of those companies are also members of the CropLife trade group, Adcock’s former employer. And they were attending in their capacity as the executive committee of the Southern Crop Production Association, according to the association’s website, not as individual company executives.

Walter M. Shaub Jr., who headed the Office of Government Ethics under President Barack Obama and during the early months of the Trump administration, said the provision cited by the USDA did not apply to the ethics regulation in Adcock’s agreement. Even if it did apply, he said, the meeting lacked a necessary diversity because the participants were all affiliated with one trade group. He also said it was irrelevant that Bray hadn’t spoken.

“If she brought them there, signed into the sign-in log, attended the meeting that she may or may not have set up, it definitely counts as a meeting with her,” said Shaub, who has been critical of the Trump administration.

Before Adcock worked at CropLife, she served as a lobbyist for the farming industry at the American Farm Bureau Federation. Among its donors is Farm Credit, a lending institution. In July, Adcock met with a delegation from Farm Credit, according to a participant.

One of the executives who attended — Jeremy Brown, president of Broadview Agriculture, a Texas cotton producer — said in an interview that he knew Adcock from the Farm Bureau. For those who did not know her, Adcock explained her past lobbying on behalf of the farming industry, and she asked for recommendations on regulatory changes, he said.

“Any time you have people already familiar with the industry, it helps,” Brown said. “They can hopefully get their feet on the ground and get the work in.”

He said he had pushed Adcock to get cottonseed reclassified as an oil seed crop so cotton producers could be eligible again for certain government subsidies if revenue dropped. He also discussed what he termed overreach on clean-water rules.

“She was taking notes, being really receptive,” Brown said.

Another highlight, he said, was the access the group enjoyed. Never before had he attended a meeting in the private gathering room just outside the office of the secretary of agriculture.

“I’ve been to the USDA a couple other times,” Brown said, “and this was the first time I’ve been able to go to what they call the Cage.”