A federal agency's efforts to ensure that workers are neither discouraged from reporting job-related injuries and illnesses nor disciplined if they do report them could upend some employers' safety programs and drug-free workplace policies.

The U.S. Occupational Safety and Health Administration's proposal dates to November 2013, when the agency said that certain employers could be required to report injuries and illnesses electronically and that OSHA would post that data online.

Employers with 250 or more workers would have to submit information quarterly, and employers with 20 or more workers in certain industries with high injury and illness rates would have to submit information annually.

Opponents cited privacy concerns and suggested that making the data public could cause employers to underreport injuries and work-related illnesses, including certain cancers and HIV. OSHA countered with a supplemental rulemaking notice last August, which states that discouraging workers from reporting injuries and illnesses through workplace policies and procedures, such as incentive-based safety programs and post-injury drug testing, would be considered a violation subject to civil penalties.

OSHA has expressed concern over the years about incentive-based safety programs that might discourage workers from reporting injuries, said Roger S. Kaplan, shareholder at Jackson Lewis P.C. on Long Island. Such programs usually offer money or other prizes when the workplace goes a specified time without an injury, he said.

In addition, OSHA said employers that retaliate against workers for reporting injuries and illnesses or failing to report in accordance with workplace policies, for example within 24 hours or at a specified location, could also face a civil penalty.

Experts say this supplemental rule should be of even greater concern to employers. But it “hasn't gotten as much notoriety as it should have ... given the ramifications of it,” said Albert B. Randall Jr., Baltimore-based principal at Franklin & Prokopik P.C. “Perhaps many people don't think it's going to go through, so they're not overly worried about it.”

However, experts and sources say the apparent lack of employer concern could stem from the fact that relatively few are aware of the revised proposal.

“This supplemental rulemaking would be the vehicle by which OSHA would come after an employer for maintaining an incentive program they didn't like,” said Marc Freedman, executive director of labor policy at the U.S. Chamber of Commerce in Washington. “They would be able to issue these citations without an employee coming forward and filing a complaint. In effect, you'd have whistleblower actions without a whistleblower.”

“On the one hand,” Mr. Randall said, “OSHA is talking about how they're trying to do this to encourage more safe workplaces, but it seems to have a contradictory effect when you take away an employer's ability to promote a safe workplace.”

OSHA also said in its plan that post-injury drug testing, used by many employers to enforce a drug-free workplace, could deter worker reporting.

If a worker who's under the influence of drugs or alcohol is injured on the job and they know they're going to be tested, they might choose not to report it, Mr. Freedman said.

“In OSHA's eyes, that means that the employer is (withholding) data,” he said.

The notice states that post-injury drug testing may be permitted if there's reason to suspect drug use. However, in states such as Alabama, Georgia and Virginia, an accident is enough reason to order a drug test, sources said. And in the majority of states, employers have the option to test workers for drugs after an injury occurs, Mr. Randall said.

“There's a strong argument that state laws are going to be pre-empted” if this rule takes effect, Mr. Randall said.

It's not realistic to require reasonable suspicion of drug or alcohol use if nobody witnessed the accident and an injury occurs, he said, adding workers can appear impaired as a result of their injuries.

“What training have OSHA compliance officers had in identifying reasonable suspicion, and are they going to second-guess employers on that?” Mr. Kaplan said. “These unanswered questions” leave employers to wonder whether “OSHA is now going to be getting into the business of second-guessing employer policies.”

Mr. Kaplan said part of the problem is that the notice contains no specifics of a final rule.

Robert Cartwright Jr., Exton, Pennsylvania-based safety and health manager of Bridgestone Retail Operations L.L.C. and treasurer of the Risk & Insurance Management Society Inc., said his biggest concern remains that injury and illness data could be made public without context.

“It's not a matter of saying we don't want to have transparency,” Mr. Cartwright said. “I don't think any company would look at it that way. If (OSHA) were to use the information that's in the Electronic Data Interchange ... most companies would be agreeable to that.”

The administration said it's still reviewing comments from the period that ended in October, and that the anticipated publication date is September 2015.

“We're left with the presumption that this is the last opportunity to comment on (the notice) before we see a final rule,” Mr. Freedman said of the far-reaching OSHA proposal.