As hundreds of thousands of refugees clamor to get in, mounting anxiety over Europe’s porous borders has generated a lucrative opportunity for companies clever at keeping people out.

The chief beneficiary may be Europe’s defense industry, which in recent years has suffered steep budget cuts at home and stiff competition abroad.

“The European arms industry has faced significant problems in the declining demand for defense projects,” said Pieter Wezeman, a defense industry expert at the Stockholm International Peace Research Institute (SIPRI).

From 2005 to 2014, defense budgets in Western and Central Europe fell by 8.3% in real terms, according to SIPRI’s analysis.

The current refugee crisis may offer a chance for defense firms to capitalize on an expanding market in border control and surveillance, according to Wezeman. Military technology – like satellites, sensors, and drones – is being repurposed to meet rising demands for border security.

The timing couldn’t be better. In its 2013 annual report, Italy’s Finmeccanica, a leading defense contractor, said that rising demand for border security and surveillance has been offsetting losses in traditional military orders.

According to market analysis group Frost & Sullivan, the global border and maritime security industry was worth $29.3 billion in 2012. By 2022, that market is estimated to reach $56.5 billion.

Which companies stand to benefit from this growth? According to SIPRI’s most recent global ranking, the largest European defense players are Finmeccanica, the UK’s BAE Systems, France’s Thales, and European multinational Airbus, formerly EADS.

Border control is already a core piece of these companies’ export portfolios. These firms have secured contracts for high-profile and high-tech border security projects in the Middle East and North Africa – in Libya and Saudi Arabia, for instance – worth billions of euros. But the present crisis provides an opening for defense firms to expand profits in their own backyard.

It is difficult to track border security contracts since much of the technology is dual purpose. Are maritime sensors on Italian naval vessels a border control technology, or a military one? How about drones, or space-based surveillance?

While the refugee crisis has focused new attention on how Europe handles its borders, European Union research and development (R&D) funding for border control technology, funneled through European defense contractors, is nothing new. For example, from 2002 to 2013, Airbus, Finmeccanica, and Thales—largely through subsidiaries—have collected the lion’s share of 225 million euros to thicken the defenses of “Fortress Europe” through the development of drones, olfactory sensors, and border patrol robots.

Europe’s big defense companies have assumed key roles on projects contributing to EUROSUR, an EU-funded surveillance system that uses drones, reconnaissance aircraft, and satellites to monitor Europe’s external borders.

“Perseus,” which integrates new and old sensor technologies on Europe’s seas and borders, is worth 43.6 million euros and includes a roster of defense partners, including Airbus, Saab, and Boeing. And “Seabilla,” a maritime surveillance project covering Europe’s Mediterranean, English Channel and Atlantic coasts, has cost 15.5 million euros. The project is coordinated by Selex, a Finmeccanica subsidiary, and includes Thales and BAE.

Implementing new technologies, and integrating them into a pan-European surveillance capability, will likely continue to boost the defense industry’s bottom line. The European Commission estimates EUROSUR will cost 244 million euros between 2014 and 2020, though critics expect it will cost far more.

The prominent role of defense contractors in supplying border services has prompted concerns about accountability and the rise of a “security-industrial” complex. Security working groups, which steer EU policy, are packed with industry representatives, according to the Migrants Files, a consortium of 15 European journalists. At the same time, these working groups lack adequate representation from the International Organization for Migration or UNHCR, the United Nations’ refugee agency.

According to the EU Observer, the security industry’s Belgium-based trade group EOS has played a significant role in EU border security legislation. Policies create industries, say the critics, which may in turn influence policy.

The drone industry is one example, some argue, of how commercial motives influence policy decisions. Ilka Laitinen, executive director of Frontex—the EU’s border control agency—told the EU Observer that drones provide a cost-effective way to monitor Europe’s borders and conduct search-and-rescue missions in the Mediterranean, saving refugees in distress. Yet it is not only the refugees who are in distress: The push for greater investment in aerial surveillance parallels commercial anxieties that Europe lags behind American and Israeli competitors in an emerging drone industry that could be worth billions. According to a 2014 market assessment by the Teal Group, global drone expenditures are expected to nearly double from $6.4 billion to $11.5 billion over the next decade.

In recent days, border fortification has intensified. Perhaps most dramatically, Hungary, which first pierced the iron curtain in 1989 by opening its border to Austria, is building a 109-mile stretch of razor wire intended to keep refugees from slipping in from Serbia. Critics say such efforts are futile and potentially dangerous. They certainly don’t address the conflicts and misery that led many to leave home and chance the Aegean in inflatable rafts, or pack into smugglers’ ships to cross the Mediterranean, which Human Rights Watch has called the “world’s deadliest migration route.”

Strict border controls simply raises the prices refugees have to pay smugglers, as well as the risks of getting in. This explains, in part, some of 2015’s calamities: the 800 migrants and refugees who drowned off the coast of Italy’s Lampedusa in April, and last month’s discovery of 71 people who had suffocated in the back of a lorry abandoned near the Austrian border.

“Lots of money goes into border controls, but this does not address the causes of migration,” said Hein de Haas, a professor of migration studies at the University of Amsterdam and former director of the International Migration Institute at Oxford University. “Instead, it helps two groups,” he said. “The smugglers and the migration control industry, while the suffering and border deaths among migrants and refugees increase.”

Still, the money spigot is unlikely to be switched off any time soon, creating commercial opportunities but also, some fret, presenting a threat to broader European aspirations. The current crisis undermines the idea of a borderless Europe, articulated under the Schengen Agreement of 1985, according to analysis from Stratfor, a global intelligence firm.

If walls continue popping up along Europe’s external borders, it may serve only to intensify the present dynamics. Between the smugglers trying to find a way in, and the private firms tasked with keeping them out, the ones likely to remain caught in the middle are the refugees.