WASHINGTON — The House Oversight Committee said Monday it is investigating whether Transportation Secretary Elaine Chao acted improperly to benefit herself or her family’s shipping company.

Two Democratic leaders sent Chao a letter asking her to turn over documents and communications related to the New York-based company, Foremost Group. Chao’s father and sisters own the company, which transports material to and from China.

“Federal regulations prohibit federal employees from using their public offices for ‘the private gain of friends, relatives or persons with whom the employee is affiliated in a non-governmental capacity,’ ” the lawmakers wrote in a seven-page letter to Chao.

China has extended hundreds of millions of dollars in low-interest loans to the company for the purchase of foreign-flagged ships.

Chao has denied wrongdoing.

Democratic Reps. Elijah Cummings of Maryland and Raja Krishnamoorthi of Illinois said they are examining Chao’s statements and actions and whether she complied with ethics rules. Cummings is the head of the Oversight panel, while Krishnamoorthi leads an economic and consumer policy subcommittee.

A Transportation Department spokesman said Monday that the department has received a letter seeking information on a variety of topics based on publicly available information and news coverage. “We look forward to responding to the committee’s request,” said spokesman Stephen Bradford. “Media attacks targeting the secretary’s family are stale and only attempt to undermine her long career of public service.”

The committee also asked Chao about her failure to sell off holdings in the construction company Vulcan Materials Co.

By Associated Press