Teens suspects in acid scare

Teenagers "up to no good" were probably responsible for a mysterious substance at a playground that ate away at the knees of an 11-month-old's jeans, the boy's mother says.

Tamsin Lockley took son Dante to the Harold Moody Reserve in Glen Eden on Thursday - his first trip to a playground. Teenagers are known to hang around the area at night.

Dante was crawling around on rubber matting when he came into contact with what Ms Lockley thinks "was some kind of acid". She says he was not injured but his knees were red and burning and he didn't sleep well for the next two nights.

The Waitakere City Council is keeping the playground closed until lab-test results are received.