it found nearly 250 cases of malignant melanoma are registered each year by those working outside in industries such as construction , agriculture and leisure .
separate study found there was a ` macho culture ' in some parts of the construction industry , with two thirds of workers who spent an average of nearly seven hours a day outdoors thinking they were unsure if they were .
the institution urged businesses to improve ` sun safety ' , for example by minimising workers ' exposure in the middle .