The emergency unit at University Hospital of Wales is treating adults and children involved in the incident in Rhoose.
The unit has specialist procedures in place for dealing with serious incidents and those have been activated to care for those involved.
The priority now is treating those involved and supporting their families.
More top news
After nearly six weeks of campaigning the race for Number 10 has reached its final stages.
Polling stations across Wales will open at 7am on Thursday May 7th. Here is a guide on 'how to' and 'how not to' vote.
Good news for voters, after an unsettled few days Thursday looks set to be largely dry with decent spells of sunshine.