By Anna Robaton / MoneyWatch
Ironworking isn't a job typically associated with top-notch perks. Yet the relatively small number of women in the trade now have something in common with workers at some marquee Silicon Valley firms. And it's not free lattes or laundry service.

Women ironworkers now enjoy one of the most generous maternity leave programs in the country: Six months of leave prior to delivery and up to eight weeks afterward. While on leave, they receive about two-thirds of their regular weekly income, up to $800 per week.

The benefit is available to women who belong to the 130,000-member Iron Workers union of North America. The union worked with IMPACT, a labor-management partnership, to design the benefit and unveiled it last month.

It puts the union's roughly 2,100 female members on par with employees at firms like Etsy (ETSY), Adobe (ADBE) and Cisco (CSCO). Only Netflix (NFLX) and the Bill & Melinda Gates Foundation offer more generous maternity leave benefits of up to a year paid parental leave for qualified employees, according to a Care@Work ranking.

Most American workers can only dream of such protections. The U.S. is among a handful of countries that doesn't require employers to provide paid parental leave, and less than 20 percent of private sector workers have such coverage.

Under the federal Family and Medical Leave Act (FMLA), employers must give qualified workers up to 12 weeks of job-protected leave a year for certain medical and family reasons -- such as the birth of a child or an adoption -- but they aren't required to pay them during that time.

Why have female ironworkers won the leave lottery? 

For one, contractors in the building trades are under pressure to employ a more diverse pool of workers to win public and private sector bids. The new maternity leave benefit is a competitive advantage in the battle to recruit and retain the limited number of female workers in the building trades.

"It's the right thing to do socially, and there is an economic issue too," said Bill Brown, CEO of St. Louis, Missouri-based Ben Hur Construction Co. and management co-chair of IMPACT, an acronym for the Ironworker Management Progressive Action Cooperation Trust.