BOSTON — The potency of certain opioid painkillers has Massachusetts’ judiciary considering whether to ban the substances from being brought into courtrooms as evidence — a move some experts say is driven by a misunderstanding of the real dangers.

The chief justice of the Massachusetts Trial Court recently told prosecutors that she fears allowing fentanyl and carfentanil into courtrooms puts lawyers, jurors and defendants at risk even when the drugs are properly packaged.

“Given their demonstrated potency and toxicity, the risk of accidental exposure, the training necessary to safely handle even though those samples that have been securely packaged as evidence, we believe a ban on these substances may be a necessary and reasonable measure,” Justice Paula Carey said in a letter.

The U.S. Drug Enforcement Agency said in new guidelines for first responders this year that even a tiny amount of fentanyl — the equivalent to five to seven grains of table salt — is enough to cause respiratory failure and possibly death. Carfentanil, which is used to tranquilize elephants, is up to 10,000 times more potent than morphine, officials say.

The Massachusetts State Police Crime Lab has said that even drugs contained in plastic packaging as evidence should be handled with nitrile gloves and that courtrooms should have the overdose antidote naloxone on hand in case there’s an accidental tear, Carey said in the letter.

Fears of the powerful drugs have been driven by reports of law enforcement personnel falling ill after coming in contact with the substances, but the stories have been challenged by professionals who say they don’t make medical sense. While powdered opioids are dangerous if they get into the bloodstream, they aren’t easily absorbed into the skin, so just accidentally touching the drugs shouldn’t make someone sick, experts say.

“If something got out and fell into a pile on the tabletop, I’d walk over and sweep it into a garbage can with my hand. I wouldn’t waste time finding a hazmat suit,” said Dr. Edward Boyer, a medical toxicologist at Brigham and Women’s Hospital in Boston.

Boyer and Dr. Andrew Stolbach, another medical toxicologist, said the drugs would pose no risk in the courtroom if they’re properly packaged.

“Concern, or even hysteria, might be natural when people are faced with something new,” said Stolbach, an associate professor of emergency medicine at Johns Hopkins University School of Medicine.

Courts have been grappling with how to handle drug evidence for decades.