Doctors sparred in a downtown Boston courtroom Friday over whether nicotine electronic cigarettes are to blame in the vaping-related lung illness outbreak that has sickened more than 1,479 people and killed 33 nationwide.

Dr. Monica Bharel, the Massachusetts public health commissioner, testified that 10 percent of patients nationwide reported vaping only nicotine, so Governor Charlie Baker’s emergency four-month ban on both marijuana and nicotine vape sales was necessary to protect people.

“Nobody knows the cause,” Bharel said, adding the ban was “a net positive for public health.”

But Boston University epidemiologist Dr. Michael Siegel testified that the outbreak is likely due to tainted black-market marijuana products and the ban pushed vapers to deadly combustible cigarettes and unregulated products.


Baker’s “order does not serve the interests of the public’s health and it actually significantly harms the public’s health,” Siegel said.

The dueling testimony came as Suffolk Superior Court Judge Douglas H. Wilkins weighed a request by vaping companies to exempt nicotine vaping products from Baker’s ban, the strictest in the country. Wilkins said he expected to rule Monday.

A group of medical marijuana patients sought this week to be included in the lawsuit filed by the Vapor Technology Association and several Massachusetts vape shop owners. They argued that without licensed cannabis vapes, they couldn’t adequately find relief for their arthritis, anxiety, ocular hypertension, and nerve damage.

Wilkins said the cannabis group could argue its case to be included in the lawsuit on Monday.

Massachusetts has so far reported 28 illnesses and one death to the US Centers for Disease Control and Prevention, and is investigating 63 more. Of those 29 cases, 20 reported vaping marijuana, seven reported vaping both marijuana and nicotine, and eight reported vaping nicotine only.

On Friday, Siegel, the BU professor, pointed to federal statistics showing that 78 percent of patients nationwide reported vaping marijuana products. He suggested that the portion claiming to have used only nicotine may have been lying about their cannabis use or have bought counterfeit nicotine vapes.


Siegel testified that the ingredients allowed in nicotine electronic cigarettes, which are federally regulated, have not changed since 2016, so it didn’t make sense to attribute a recent rash of new illnesses to those products.

But Bharel, the public health commissioner, testified that the state’s first vaping-related death, a Hampshire County woman, had used nicotine only and her urine tested negative for marijuana. She also said she didn’t know where the woman purchased her nicotine vape.

And Bharel acknowledged that the state has not tested any samples of vape products, but sent them to federal investigators for testing.

Dr. Alicia Casey, a pediatric pulmonologist at Boston Children’s Hospital, testified that she has treated at least six patients with the illness. Although cigarettes wreak havoc over years, she said, they don’t cause the type of severe acute short-term lung damage she has seen with vaping.

“I do still consider 10 percent of patients getting ill and having a life-threatening respiratory illness as a significant number,” Casey said.

Bharel and Casey both cited federal authorities investigating the outbreak who said they could not rule out nicotine as playing a role. They believe that the illness has multiple causes.

One plaintiff, Behram Agha, an owner of Vapor Zone in Saugus, Danvers, and Norton, said after the hearing that he had to lay off 11 employees and permanently close his shop in Ipswich.


“The vape shops have been doing the right thing” and following all state rules, Agha said, and shouldn’t be punished for bad actors in the illicit marijuana and nicotine markets.

But concerns about jobs or businesses didn’t weigh into Baker’s decision to ban the product sales, Bharel testified, only the rapidly rising number of reported illnesses.

Naomi Martin can be reached at naomi.martin@globe.com. Follow her on Twitter @NaomiMartin.