London (CNN Business) US stock markets were halted briefly Monday as a record fall in oil prices and fears of the coronavirus triggered panic selling. But the epidemic poses a much bigger logistical headache for Wall Street — how to keep trading going if banks have to evacuate their offices to fight the spread of the illness.

Global banks are already scrambling to split their workforces to reduce the risk that large numbers of employees fall ill, and testing backup sites to ensure they can continue doing business even if they can no longer access Wall Street or locations in central London.

has started dividing its sales and trading teams between separate offices. It told employees in an email that this is a "precautionary measure" to make sure the bank can continue to run smoothly. The firm runs alternate sites in Brooklyn and New Jersey, and in Basingstoke, about 50 miles southwest of London.

said it is splitting its fixed income and equities trading teams from Monday, sending some people to a backup site in Stamford, Connecticut.said it has split some London operations and trading teams, with some employees working from home.

Traders athave ramped up testing of their ability to work from home and alternate sites, according to a source familiar with the investment bank's plans., which had to deep clean a floor of its London headquarters last week and send some staff home after an employee contracted the virus, said that it had invoked split-site working arrangements for its teams in Asia, and that it does not expect any disruption to services in Europe.

Blackrock BLK Investment firmsaid Tuesday that an employee at its New York office had been diagnosed with coronavirus and was working from home. The firm said it had conducted deep cleaning of the area where the person works, and asked people who had been in close contact to work from home for 14 days.

"Our business continuity plans are working as planned. This includes provisions for teams to alternate working from the office and from home to limit potential exposure," it said in a statement.

Still, the coronavirus pandemic poses the biggest logistical challenge for the finance industry since Hurricane Sandy in October 2012, and before that, the terrorist attacks on September 11, 2001.

Operating large dealing rooms, where employees crowd to trade stocks, bonds, currencies and commodities, is looking increasingly untenable as the number of confirmed cases of coronavirus in New York and London climb. That's left banks to explore other options to keep trading going, while dealing with a global stock market rout.

Goldman Sachs is testing a building in Croydon to run backup trading operations. It's about 9 miles from central London.

Worse than Hurricane Sandy?

When Hurricane Sandy flooded large parts of Lower Manhattan, the US's primary financial center, trading was suspended on the New York Stock Exchange and Nasdaq for two days.

That marked the first wholesale closure of markets since 9/11, when exchanges were closed for four days following considerable damage to physical and electronic infrastructure caused by the destruction of the World Trade Center.

By the time Hurricane Sandy hit 11 years later, most large financial firms had disaster recovery sites within 50 to 100 miles of New York City, said Damian Handzy, chief commercial officer at investment analytics firm, Style Analytics. Handzy was CEO of a Wall Street risk analytics company during Hurricane Sandy and 9/11.

The hurricane caused power outages in more than a dozen states, affecting backup sites even in New Jersey and Pennsylvania. This made it challenging for the financial sector to carry on as normal, especially since many employees were dealing with flooding and electricity outages in their own homes, Handzy told CNN Business.

Likewise, the coronavirus could take a personal toll on a large number of employees at the same time if their children are forced to stay home from school, family members need care, or they need to self isolate.

"We don't know how people will behave," Handzy said.

But banks are much better prepared for remote working than in 2012, and cloud-based technology means analysts and traders are able to work from "pretty much anywhere."

"I don't think the markets will shut down because of this," he added.

The Securities Industry and Financial Markets Association, a Wall Street trade group, said it tests each year the industry's ability to operate through a significant emergency using backup sites, recovery facilities and alternative communications. It's been discussing the preparedness for the coronavirus for about two months, SIFMA CEO Ken Bentsen told CNN Business.

SIFMA, which last tested the industry's resilience to a pandemic in 2007, is confident that firms can operate from remote locations using backup facilities, added Tom Price, head of technology, operations and business continuity.

A spokesperson for the New York Stock Exchange said it regularly tests contingency plans to "enable continuous operation of the NYSE exchanges should any facilities be impacted."

Technical and regulatory hurdles

Working from home or backup locations won't be straightforward, however. Widespread use of disaster recovery sites or home offices could give rise to technical problems, as trading software and compliance systems require a lot of bandwidth. And some trading platforms don't allow remote log-ins.

Regulation complicates matters further. To comply with the rules governing markets, calls need to be recorded, and compliance teams need to be readily accessible.

Price said that SIFMA has been discussing record-keeping and supervision requirements with US regulators, in the event that traders have to work remotely.

"We may need some guidance or temporary relief if the goal is to keep markets moving," he said.

The UK Financial Conduct Authority said in a statement that it is working with financial firms to review their contingency plans, but expects companies to "be able to enter orders and transactions promptly into the relevant systems, use recorded lines when trading and give staff access to the compliance support they need."

If firms can do this by running backup sites or with staff working from home, the FCA said it has no objections.

The European Central Bank has told banks to "urgently" test whether "large scale remote working or other flexible working arrangements for critical staff can be activated and maintained to ensure business continuity."

Banks should also assess whether alternative backup sites can be established, the ECB said in a statement.

Customer service representatives work inside a call center at First Direct bank, a unit of HSBC.

Call centers face difficulties

The call centers that serve customers of banks, insurers and other financial services firms may also face disruption.

UK call centers would manage to put only about 10% to 15% of people into a home working situation overnight, said David Freedman, the CEO of Confero.

The United Kingdom has about 6,000 call centers employing some 900,000 people, or about 4% of the workforce, he told CNN Business. About 18% of these centers serve the financial sector, with 16% serving retailers. Only about 3.5% are set up for homeworking.

As with banks, remote working poses unique challenges around security and data protection. Confero's agents handle sensitive personal data, as they field calls from the customers of insurers and credit card companies. If they work from home, it's impossible to monitor how they are managing confidential information, Freedman said.

"We don't vet our staff for what their home environment is like," he added. "Sensitive information is displayed on an agent's screen, and it's impossible for us to know who is walking into and out of a room."

Freedman, who is a board member of the Data and Marketing Association's Contact Centres Council, said the council is meeting this week to discuss the potential disruption that the coronavirus could cause call centers.

— Clare Sebastian, Eoin McSweeney and Cristina Alesci contributed to this report.