A police officer with a dog patrols Wednesday in D.C.’s Union Station. (Joshua Roberts/Reuters)

Even before the terrorist attacks in Brussels on Tuesday, businesses have been placing increasing emphasis on security in a tacit acknowledgment that any place serving a large gathering of people can be a target.

The Brussels attacks took place at an airport and subway station and came just months after coordinated terrorist attacks in Paris were carried out at venues such as cafes and a concert hall. Elsewhere, earlier incidents took place at shopping malls and sports events.

“There is a much broader accepted awareness about the fact that this is now an everyday job. This is not something you react to,” said Michael W. McCormick, executive director of the Global Business Travel Association.

The preparations could be seen in the swift response around the globe. On Tuesday, coffee giant Starbucks announced that it was closing all of its stores in Belgium “until further notice.” Several airlines and hotel firms quickly announced that they would honor last-minute cancellations.

In Washington, meanwhile, organizations of all kinds beefed up their vigilance. Amtrak police, for instance, alerted its retail partners at Union Station that it was putting extra precautions in place.

“Amtrak Police are working with state, local and federal law enforcement partners to gather and share intelligence,” Amtrak said in a statement. “Extra officers have been deployed. We have reminded Amtrak employees to look for and report any suspicious activity and unattended items and reissued guidance pertaining to facility inspections and active shooter incidents.”

Jim McNulty, executive vice president at security firm Securitas, said corporate clients have been regularly retooling their operating strategies to gird themselves for such an environment.

“What we’re seeing is not necessarily a ramp-up in spending but a ramp-up in a much more comprehensive and holistic approach to the security situation,” McNulty said.

That means, McNulty said, clients are often expanding their approaches to include services such as mobile patrol and remote guarding, technologies that he said have improved dramatically in recent years and that cost far less than they used to.

Kastle Systems, the largest provider of electronic access and video networking to office buildings in the Washington area, has seen revenue grow more than 60 percent since 2009, according to owner Mark D. Ein. He said the company recently committed to providing at least 500 video cameras to D.C. businesses through a partnership with law enforcement in which building owners’ agree to link their cameras to the police, allowing officers more rapid access to footage of public spaces such as sidewalks, alleys and streets in the event of a crime or attack.

“That’s growing really fast and, in the aftermath of recent events, has become more popular,” Ein said.

Security procedures are a regular preoccupation at Akridge, the D.C. commercial real estate firm that manages 26 buildings in the area. After hearing of the Brussels attacks, Akridge sent a message to companies in their buildings reminding them of emergency procedures and protocols, said Kathy Barnes, senior vice president of property management.

Barnes said that buildings are equipped with ever-increasing methods for keeping employees safe, among them glow-in-the-dark paint and signage in stairwells in case the power goes out. In the event of a chemical attack, some buildings now have plastic covers that can easily be attached to doors to prevent poisoned air from seeping in, as well as “kill switches” that allow security or maintenance workers to immediately turn off all heating, cooling and ventilation systems. Management teams also make sure that not only fire extinguishers but also axes and hand-crank radios are available.

“We’re all doing things we’ve never done before since 9/11. It’s a whole new ballgame and it is getting more and more complex,” Barnes said.

A critical component is making sure workers are regularly reminded and trained on important procedures. Barnes said she contacts tenants once a month either with a written reminder or a training in the building lobby on how to use emergency equipment or the importance of having evacuation plans, emergency phone numbers and “go packs” filled with essentials.

Concert venues have been under additional scrutiny since the November attacks in Paris, which included gunmen firing into the crowd at a rock show. Airportlike searches are already the norm for entry at the Verizon Center in downtown Washington. A spokeswoman for the arena’s owner, Monumental Sports & Entertainment, said that security remained the company’s “top priority” and that it was regularly in touch with local law enforcement.

Retailers, meanwhile, “recognize their unique responsibility” in preparing for threats and emergencies, said Bob Moraca, the vice president of loss prevention at the National Retail Federation.

“Retailers will remain vigilant and proactive as they work with each other and domestic and international law enforcement agencies to bolster their security preparations after events like what took place in Brussels,” Moraca said in a statement.