(Newser) – Today's the day Los Angeles porn stars are supposed to start covering up. A new city law goes into effect, requiring that condoms are used during porn film shoots. Film licensing fees will fund enforcement of the law, which was fought by porn production companies, who are threatening to leave the city because of it. The law, believed to be the first of its kind anywhere, was enacted after several porn stars contracted HIV. The AIDS Healthcare Foundation, which helped spearhead the law, is now gathering signatures for an initiative to take the measure county-wide, reports the Los Angeles Times. (Read more condom stories.)