The former head of Newfoundland's largest health board says he didn't tell his counterparts at the province's other health boards about breast-cancer testing errors until two months after he discovered them.

But former Eastern Health CEO George Tilley told an inquiry today it wasn't a deliberate decision because he thought the lab may have contacted them.

Half the botched breast-cancer tests involved people who were patients of those other health boards.

Tilley became aware of the testing errors in July 2005, but he says he can't recall telling the CEOs of the other health boards until September of that year.

The inquiry is looking into how nearly 400 patients received the wrong results on their breast-cancer tests.

It is also trying to determine whether Eastern Health or any other responsible authorities responded to patients and the public appropriately.