Emmanuel O. Irono started his business by cleaning houses -- vacuuming, washing windows and scrubbing alongside two employees -- even though he had an MBA and training as a budget analyst.

"I stored the smelly buckets in my apartment," he said. "I suffered in silence and stayed focused."

Fourteen years later, Motir Services Inc. has 500 employees, $12 million a year in revenue and three divisions that provide cleaning, construction and medical staffing to government agencies.

The Nigerian immigrant's company is representative of many in the Washington area, a hub for minority-owned firms, including many owned by immigrants. Most are one-person enterprises with no paid employees and modest revenue. Some grow and prosper, especially if, like Irono's, they thrive on government contracts.

On a recent morning, the president of Motir Services was running late for an appointment. He had a good excuse, his assistant said: The previous day, Irono was in Nigeria working with a children's foundation he supports.

Despite the nine-hour flight, Irono showed no signs of jet lag when he arrived at the Capitol Heights industrial park that serves as his company's command center.

He settled into his office, which reflects his life and business. A file cabinet behind his desk is decorated with a picture of Irono and District Mayor Anthony A. Williams (D) wearing hard hats at the construction site of the Anacostia Gateway, where Irono's company won part of a major construction contract. Beside the photo is a scratched wooden mask that was hand-carved by an African artisan and discovered by Irono among his late grandmother's belongings in Nigeria.

Irono came to the United States as a foreign exchange student and planned to return to Nigeria after college to work for his father's construction company. But when both of his parents died within two years, he decided against returning and began paying his tuition by working as a school janitor.

After graduating, Irono took a job working as a budget analyst for a federal contractor. But he wanted to start his own firm, and he bought out a small janitorial service company's supplies for $10,000. He renamed the company Motir, an amalgam of his parents' initials.

Now his office has a black leather couch and a slick silver digital business-card holder that flashes the words "Emmanuel Irono, Motir Services, President."

Irono, 42, traces the company's growth to a $100,000 contract he won during Mayor Marion Barry's administration to clean the D.C. National Guard Armory. That eventually led to cleaning, maintenance and staffing contracts with the National Institutes of Health, the Army Corps of Engineers, the Washington Convention Center and the District of Columbia Public School system.

Irono won those contracts, in part, because he qualifies for District government contracts that are set aside for local small, minority and disadvantaged businesses. Motir is also a Small Business Administration 8(a) company, which allows him to apply for contracts that the federal government has targeted at businesses owned by minorities.

Next year, Motir will focus on expanding its construction and medical staffing divisions. This summer, he won a $14 million joint contract with Forrester Construction Co. to build the Anacostia Gateway office building, an anchor of the redevelopment project in Southeast Washington.

Still, Irono said he keeps in mind the smelly buckets and mops upon which Motir was founded.

"There was a bumpy road in the start," he said. "It was very humbling for me."