In his New Year's message, Sir Digby Jones, the director-general of the CBI, will respond tomorrow by warning companies to be better prepared in future for emergencies such as the Hemel Hempstead blaze and the London terrorist attacks last July.
Businesses need to look again at their contingency plans, many of which were shown to be inadequate last year, Sir Digby will say.
The blaze destroyed large parts of a business park adjoining the depot site. Among the firms based in the park were Steria and Northgate Information Solutions, both of which store data on behalf of clients.
Some companies whose data and systems were stored on the site have been complaining to the CBI that their operations are still being disrupted as a result of the 11 December fire.
One City insider said that companies were having to rebuild their systems from scratch, as some of the information cannot be retrieved.
Northgate, which has its headquarters at the site, suffered the worst damage from the blaze. It admitted in an announcement to the stock exchange the following day that its back-up systems were "rendered inoperable". "Northgate's ability to service its customers has therefore been temporarily affected," it added.
It has since emerged that the blaze could not have happened at a worse time for the company. Northgate duplicates its clients' information on computers at the site. At around 7am every morning a courier would collect the data on disk to take off site for safe storage. Because the blaze happened at around 6am, before collection, a whole day's worth of data collected on behalf of clients was destroyed.
A spokesman for Northgate conceded it might take another couple of weeks for all the data destroyed to be retrieved, but denied that any permanent harm had been done. "No data has been lost for good as a result of the Buncefield explosion," he said.
Haringey Council in London, a Northgate client, has not been able to accept council tax payments online since the fire.
A spokesman for the Local Government Association said: "Haringey does not think it has lost any information. But Northgate is going to have a lot of work to do."
Northgate also stores customer billing information for utility companies. But a spokesman for the Energy Retail Association, which represents energy suppliers, said it was not aware of any customer records being lost as a result of the blaze.
John Torrie, the chief executive of Steria, whose clients include the insurance market Lloyd's of London, said services had not been interrupted for customers, such as financial institutions, that run systems on which their businesses depend.
No client information was lost as all data was stored off site. But "one or two" companies had not taken out a business contingency service with Steria, which meant recovery of the information would take longer, he said.
Lindsay Armstrong, a senior vice-president of the internet security and data management company Symantec, said there needed to be a change in the way the risk of technology failure was viewed at boardroom level.
"We need to learn from incidents like the attacks of 11 September in the US that no risk is too remote," she said. "Small and medium-sized businesses need to be more aware of how to protect themselves. It's important to test back-up systems. Some companies do not, and believe that they are paying data storage companies to guarantee their safety.
"But there is a real risk of losing data. If there is no back-up, the only way to deal with it is to input the lost data again. In some cases this may not be possible."