Theme parks and fairgrounds in the UK have been urged to ensure that staff are properly trained after the operator of Oakwood Theme Park in Pembrokeshire was fined £250,000 for an incident which led to the death of a teenage girl in 2004.

Oakwood Leisure was also ordered to pay £80,000 costs by a judge at Swansea Crown Court on 18 December after the company pleaded guilty to a health and safety charge of failing to ensure visitors were not exposed to any risks. The Health and Safety Executive (HSE) said that the death of 16-year-old Hayley Williams, who fell 100ft (30.5m) from the park's Hydro Ride in April 2004, should serve as a warning to other operators.

HSE inspector, Phil Nicolle, said: "This tragic case should serve as a warning to all fairground operators that safety must be their top priority. "Fairgrounds, including theme parks, attract and entertain millions of people safely each year but regrettably accidents and incidents do happen. Yet the majority of incidents are, as in this case, caused by management failings."

The HSE added that an investigation into Oakwood Theme Park found that there were "systematic failures" in the training and supervision of staff. In response to the HSE's comments, Colin Dawson, BALPPA chief executive, said: "The HSE comment was somewhat unfortunate, coming as it did in the very month that the HSE confirmed a further drop in the annual accident rate on fairgrounds and amusement parks.

"Their figures show that since the introduction of ADIPS, the industry accident rate has reduced by 82 per cent, which was referred to by Barry Baker, HSE principle inspector as 'a compliment to the way in which the industry has developed its self-regulatory scheme'. "Our industry will always place the safety of our customers and employees as the number one priority, even with these impressive figures complacency will never be considered an option."