The AARP filed a lawsuit in federal court inWashington last week seeking to enjoin final rules for workplacewellness programs recently issued by the Equal EmploymentOpportunity Commission, claiming they allow employers to illegallyaccess private health information of employees and use the data ina potentially discriminatory manner.

Related: Do wellness plans discriminate againstolder employees?

The AARP, which represents almost 38 million people age 50 orolder, alleges that the rules, which the commission finalized in May, violatethe Americans With Disabilities Act and the Genetic InformationNondiscrimination Act.

But lawyers representing employers say the injunction wouldincrease uncertainty around programs intended to lower medical andhealth insurance costs, which already are being adopted by manyorganizations in the U.S.

The federal Affordable Care Act has encouraged companies tooffer wellness programs, which are intended to incentivizeemployees to get help with weight loss or smoking cessation inexchange for lower insurance premiums.

Related: 4 reasons to welcome EEOC wellnessrules

Steve Wojcik, vice president of public policy for the NationalBusiness Group on Health, a nonprofit that represents employers'perspectives on health policy issues, said, "these incentives arenot designed to penalize people, they are encouraging people tostay active and healthy and engage in wellness and lower theirrisks."

The organization released a statement in May sayingthat for most large employers the final EEOC rules were "businessas usual."

But the fact that many of these programs require employees toundergo health-risk assessments or biometric screenings has raisedcontroversy over whether they violate workplace privacy laws. Thereis also a question of whether the programs are truly voluntary, orwhether the higher costs for nonparticipants may be coercive.

The AARP's lawyers from the organization's litigation arm, AARPFoundation Litigation, wrote in their complaint filed in the U.S.District Court for the District of Columbia that Congress intendedthe Americans With Disabilities Act and the Genetic InformationNondiscrimination Act to "generally prohibit employer requests foremployees (and dependents') medical data" with only "narrowexceptions" for "strictly voluntary" programs.

"For 15 years, consistent with Congress' intent, the EEOCmaintained that employee wellness programs implicating confidentialmedia information are voluntary only if employers neither requireparticipation nor penalize employees who choose to keep theirmedical and genetic information private. The 2016 rules departstarkly from the EEOC's longstanding position" the complaintstates.

The final rules issued by the EEOC, which declined to comment onthe suit, said that in order to be voluntary, companies can'tcondition health coverage on wellness program participation. Theyalso can't offer an employee a penalty totaling more than 30percent of the value of an individual's plan for not participatingin a wellness program.

The complaint claims that this 30 percent threshold stillpenalizes nonparticipating employees too much. AARP lawyers pointto data from the National Women's Law Center that says that 30percent of an employee's coverage in 2014 worked out to an averagetotal of $1,800, or more if a spouse is on the plan.

"To the average person that's going to make a really bigdifference in their monthly budget," said Dara Smith, one of theattorneys representing the AARP. She added that the AARP'spreference "would be for employers not to penalize people at all"for nonparticipation.

Smith also pointed to the dangers of having health datadisclosed to employers, particularly when the employee is older."Older workers tend to be the ones who are disproportionatelylikely to have the sorts of conditions revealed by these inquirieslike high blood pressure, diabetes or mental health concerns likedepression," she said.

If an employer becomes aware of one of these issues throughwellness program testing, she argued, they could takediscriminatory action like laying off older employees to keepinsurance costs down.

Attorneys representing employers in benefits matters say thatdespite debate over the legality of employee wellness-programdisclosures, many companies are adding them.

"We've seen a pretty large uptick in wellness programs beingimplemented and strengthened, and made more robust over the pastseveral years," Garrett Fenton, a partner at Miller & Chevalierin Washington who represents employers in employee benefitsmatters.

Frank Morris Jr., a partner at Epstein Becker & Green inWashington who also works on employee benefits cases, said that thepossibility of an injunction that eliminates the EEOC rules creates"additional uncertainty" that could be "very harmful" for employerscurrently planning employee health insurance and other benefitsregistrations for 2017.