LONDON (AP) — A long-awaited inquiry is opening in Britain into how contaminated blood was used to treat thousands of people in the 1970s and '80s, killing at least 2,400.

Thousands of hospital patients - many of them hemophiliacs - were infected with HIV or Hepatitis C through tainted blood products, largely imported from the United States.

Previous investigations have been branded a whitewash by victims' campaigners. In 2017 Prime Minister Theresa May ordered a new inquiry, with the power to summon witnesses.

As hearings began Tuesday, May said "today will begin a journey which will be dedicated to getting to the truth of what happened and in delivering justice to everyone involved."

The inquiry, led by a retired judge, will spend months hearing from victims in London and around the country.