New York City Mayor Michael Bloomberg has always taken a realistic position in debates about the fate of undocumented immigrants, approaching the subject as a pragmatic businessman, not as a moralist or a lawyer. He firmly believes that our society, particularly New York City, needs undocumented immigrants since they take jobs that many Americans and legal immigrants would not want to do.

The New York Building Congress has recently published a report, proving that the realist-mayor is right. Businesses in the world's capital – at least those in the construction industry – need undocumented immigrants.

The New York Building Congress, a leading group in the industry, includes construction companies, real estate and interior design firms. The 275,000 people in this group include engineers, architects, designers, real estate agents, and, of course, construction workers, who make up the majority of the group with 123,000 members.

According to figures released by the New York Department of Labor, the number of construction workers has increased by a record 15 percent over the past two years, fueling the construction boom in the city.

The traditional image of a construction worker has changed. Not long ago, they were mostly middle-aged "rednecks" from small towns who came into the city for work. Now the majority of construction workers are young people who live in the city, but were born and raised abroad. Over the past 10 years, the average age of construction workers has fallen from 51 to 40. Forty-seven percent of workers are immigrants. The New York Building Congress does not specify how many of these immigrants are undocumented, but judging by statements made by its president, Richard Anderson, a good deal of them are.

Anderson and other senior officials at the New York Building Congress admit that they have already experienced a shortage of workers. They are nervously following events on Capitol Hill, where the issue of comprehensive immigration reform is being debated. Since Democrats hold the majority in both houses of Congress, this issue will most likely be settled in favor of undocumented immigrants already in the United States. But immigration legislation blocking new waves of undocumented immigrants from entering the country could have an unfortunate effect on the New York construction industry as a whole.

The paradox is that the boom itself, particularly the record growth in real estate prices, could also have an unfortunate effect on the industry. The lack of affordable housing in New York has forced many low- and middle-income people (including people in the construction industry) to move to other cities and states where nice houses and apartments (as well as rents) are less expensive. The majority of New York construction workers (72 percent) now live in Brooklyn and Queens, while the majority of real estate agents reside in Manhattan. New York's construction industry clearly has an interest in keeping all of its workers in one of the five boroughs in the future as well.