Internationally, some healthcare facilities introduced policies in 2007 regulating Crocs. Rapid City Regional Hospital in South Dakota changed its dress code to prohibit the sandal variants and those with holes, citing safety concerns, but allowed closed-top "Professional" and the healthcare-focused "Rx" Crocs to be worn. Over 100 hospitals in Canada were advised to implement similar policies. Blekinge and Karolinska University hospitals in Sweden banned the wearing of "Forsberg slippers" ("Foppatofflor") by staff, due to high voltage static electricity buildup which was observed to interfere with electronic equipment. City hospitals in Vienna, Austria announced banning Crocs, often worn by nursing staff, to comply with antistatic requirements.