WASHINGTON — Equifax Inc (EFX.N) failed to patch a software security vulnerability after being alerted in March by the U.S. Homeland Security Department to the issue that led to hackers obtaining personal information from over 140 million Americans, the company's former chief executive will tell Congress in written testimony made public Monday.

"It appears that the breach occurred because of both human error and technology failures," said former CEO Richard Smith, who apologized for the breach before his appearance before a U.S. House committee on Tuesday and said the company is taking a number of steps to better protect personal data.