By the time O’Brien made her last trip to Dubai, a two-week special-inspection project in the spring of 2006, imports from the U.S. had increased by billions of dollars, as had the stream of gray-market goods continuing on to Iran. When I tell O’Brien I heard that about 40 percent of U.S. cargo is being there, she says that figure represents “just what we can account for.”

Today, many share O’Brien’s belief that some American companies are intentionally using Dubai as a conduit into Iran. “They would have to be extremely stupid not to know that their products are going to Iran,” says Rochdi Younsi, the Middle Eastern analyst for the Eurasia Group ­in Washington. “They do know.”

“I think a majority of these companies are well plugged-in in Washington,” he continues. “In D.C., they are given mixed signals, but they have more reason to believe that the U.S. is not going to take any action against them. So they go ahead and do it.”

There are dozens of American companies involved in the gray market with Iran. In both Dubai and Iran, I see Apple, Black & Decker, Dell, Hewlett-Packard, Procter & Gamble, and Xerox. With the exception of Apple, all have offices in Dubai’s free-trade zones.

The website of H.P., the U.S. technology brand I find most often in Iran, lists U.A.E. “partners” from whom locals may buy its products. Although Anette Nachbar, an H.P. spokeswoman, says that the company “does not have operations­ in Iran” and complies fully with U.S. export laws, H.P. has partners in Dubai who are eager to do business with Iran.

I call a number of these U.A.E. partners of H.P. and ask if they ship printers to Iran. The first three are ready to make deals. Another company, Jumbo Electronics, says it can offer H.P. laptops and notes that if anything needs to be fixed that falls under warranty, there are many authorized H.P. service providers in Tehran. In Dubai, one distributor on the creek promises that he can get 200 All-in-One printers in two hours and ship them to Iran. “If anyone asks, I’m the end user,” he says, using the language of the U.S. sanctions. When I ask H.P. if the company knows this is going on, Nachbar responds, “We’re just not in a position to disclose more information.”

Dell also indicates that it doesn’t sell to Iran, but like H.P., the computer maker seems to be turning a blind eye when it comes to its distributors. Even though Metra Computers, one of a handful of local distributors listed on Dell’s website, says it can handle bulk orders to Iran, its contracts with distributors ban reselling to Iran. A Metra salesman says that the company can’t ship directly to Iran, but he knows of “many” third parties that “do that consistently.” He adds, “My objective is to make new customers. We are big-time into Dell.”

Black & Decker’s approach is slightly different. I find at least a half-dozen stores in Tehran selling the company’s tools. Some feature big billboards advertising the company as well as its latest drills and handsaws. In addition, Black & Decker’s website actually lists a store in Tehran. When I talk to Roger Young, a company spokesman, he explains that the Tehran store is unrelated to the parent company in the U.S. and that any business between Iran and Dubai, or anywhere else, goes through its “non-U.S. subsidiary”—another loophole in U.S. rules that allows companies to deal with a sanctioned country as long as there is no American oversight. So instead of moving through middlemen, Black & Decker products are sold in Iran through an unaffiliated foreign subsidiary.

When I press Young for more information about Black & Decker’s business in Iran, he says that the Middle East represents less than 2 percent of the company’s business.

Procter & Gamble is another corporation using non-U.S. subsidiaries for dealings with Iran. Rotha Penn, a company spokeswoman, explains, “Were we to stop this legitimate activity, it is likely that inferior, counterfeit products would be sold to consumers instead of the genuine brands.”

Recent U.S. Securities and Exchange Commission filings for both Procter & Gamble and Black & Decker make no reference to Iran.