Flor Rivillas went to work every day, but she had no idea where. An anonymous white van took her from her apartment in Chelsea to a factory at an undisclosed location, where she worked 16-hour shifts packaging and hauling books and boxes.
Her paycheck offered no hints about the company or the temp agency that hired her, because she was paid in cash.
“I don’t know the name of the temp agency, I don’t know the name of the employer,” the 49-year-old Rivillas, who speaks Spanish, said through a translator. “It’s not right.”
Stories like Rivillas’s are increasingly common, worker advocates said, and show the state needs to step up enforcement and close loopholes in state laws that aim to protect temporary workers from unscrupulous staffing firms. The state labor department is in the process of writing and updating regulations to clarify and eliminate ambiguities in laws related to temporary employment agencies.
Under a law enacted nearly two years ago, for example, temp agencies are required to give workers information in writing about the pay, hours, and locations of jobs, but it is often provided in languages that the workers, frequently immigrants, don’t understand.
They are also required to post notices of the rights of workers to know these basic details of their employments, but some post them out of sight — or not at all.
Rivillas said she worked for more than a year while unsure of the city or town where she was working. Three years ago, she came to the United States to work and send money to Colombia to help support her mother and two children.
She said a recruiter she had never met contacted her one day by phone, asked whether she wanted a job, and told her where to meet a van in East Boston that would take her to one. With no other details, but with few work options and bills to pay, she agreed.
In an interview, Rivillas described harrowing rides from East Boston in overcrowded and bug-infested vans that reeked of urine and were never air-conditioned or heated. She said one driver, in particular, often appeared to be drunk.
“It’s frightening,” she said. “The hardest part is seeing the other people on the van weeping because they are so scared.”
Recently, more than 20 temp workers, including Rivillas, testified in Boston about temp agencies and conditions that did not follow the law. Many spoke of similar experiences, including being transported to work in overcrowded vans from East Boston to parts unknown.
“We want to make sure the state vigorously enforces the law and makes it real, makes it help people,” said Richard Rogers, executive secretary and treasurer of the Greater Boston Labor Council, which represents 161 unions throughout metropolitan Boston.
“This is a national issue of the exploitation of day laborers. They don’t know where they’re going, where they’re working, and they don’t know the conditions.”
Stephen Dwyer, a spokesman for the American Staffing Association, a trade group in Alexandria, Va., said most temp agencies give workers all the information they need about their employment and pay, but added some of them are “bad actors” that need to be brought into compliance with the law.
“For our industry, our most important asset is our workers,” Dwyer said. “It does no good to keep them in the dark.”
The state is reviewing and writing regulations for temp agency laws from the 1960s as well as the Temporary Workers Right to Know Act, passed in January 2012. The right-to-know statute was passed in reaction to a rising number of agencies apparently violating wage and overtime laws.
Workers seeking to ensure they received the minimum wage, overtime pay, and other rights — often in tandem with unions and other advocacy groups — were having trouble identifying such basic information as the name of the company that employed them.
In the first year since the Temporary Workers Right to Know Act became law, the state labor department conducted 66 mostly random inspections of temp agencies that resulted in three cases that were referred to the attorney general’s office for enforcement.
A spokesman for the attorney general’s office said two of those cases have been dismissed, and the third is ongoing.
The state Department of Labor Standards is in the process of finalizing regulations related to temp agencies and how they will be enforced. Heather Rowe, the agency’s director, will ultimately decide on the regulations, including, for example, where signs alerting workers to their rights will be posted.
She said she hopes to issue a final set of rules by the fall.
Marcy Goldstein Gelb, executive director of MassCOSH, a workers advocacy group, said her organization has suggested requiring temp agencies that transport workers to post information about their rights inside the vans.
“This is a very common and a growing thing,” Goldstein-Gelb said of workers unable to identify their employers. “In order for this law to fully work, we need to have those rights posted.”
Advocates say temp workers, often desperate to make a living and with few job protections, are particularly vulnerable. Many, seeing little other choice, take dangerous and undesirable jobs in substandard working condition, sometimes with dire consequences.
In June, federal officials fined a New Bedford shellfish processing plant and the temp agency it used a total of $44,000 for safety violations that contributed to the death of Victor Gerena. The 35-year-old father of five died earlier this year after he became entangled in a clam-shucking machine he was cleaning.
In 2011, Daniel Collazo died after he was crushed while cleaning a machine at the Tribe hummus plant in Taunton. Tribe, a subsidiary of the Swiss conglomerate Nestle SA, hired him through a temp agency in Fall River. Collazo, 28, had been on the job only a few months at the time of his death.Megan Woolhouse can be reached at megan.woolhouse@ globe.com. Follow her on Twitter @megwoolhouse.