Safety, health and environmental technology group Halma said strong oil and gas demand and medical acquisitions drove record first-half profit.Halma, which makes fire and smoke detectors, water disinfection technology and devices used in eye surgery, said its process safety division increased revenue by 8% as oil and gas companies sought to improve safety.The group's medical division boosted revenue 36% to £81m, boosted by strong performances in the US, Asia Pacific and Middle East, while recently acquired businesses had done well.Profits in Halma's environmental and analysis arm fell 3% to £15m due largely to a shake-up in its photonics businesses and costs in its water monitoring operation.It said the photonics restructuring was going well and the environmental division should be well-placed at the end of the year to start increasing profits again. Shares rose 4.5p to 575.5p by 11.33 in London.Chief Executive Andrew Williams said: "Order intake since the period-end has continued to be slightly ahead of revenue and in line with our expectations. Halma remains on track to make further progress in the second half." PW