Doctors studying lung tissue from people with vaping-related injuries have ruled out one diagnosis as a probable explanation of how vaping harms the lungs, further deepening the mystery over the exact cause of hundreds of illnesses in the United States.

A U.S. House panel sent letters to four e-cigarette companies asking them to stop all print, broadcast and digital advertising of their products in the United States.

Juul Labs said the company would suspend all broadcast, print and digital product advertising in the United States and replaced CEO Kevin Burns.

Massachusetts imposed a four-month ban on sales of all vaping products, amid what officials called a national public health emergency that so far has been linked to nine deaths.

The number of Americans sickened by a severe vaping-related illness continues to increase, according to a U.S. health official speaking at a Congressional hearing.

A bipartisan group of U.S. senators urged federal regulators to immediately remove all pod and cartridge-based e-cigarettes from the market until the products can be proven to be safe.

U.S. health officials said there are 530 confirmed and probable cases and seven deaths from severe lung-related illnesses tied to vaping, and there are no signs that the outbreak is easing.

An independent expert panel to the U.S. FDA recommended approval of GlaxoSmithKline Plc’s over-the-counter nicotine oral spray that aims to help smokers quit their addiction.

Congressional Democrats threatened to subpoena Juul Labs if the e-cigarette maker does not provide documents relating to the company’s products and marketing practices, as a House panel looks into whether Juul deliberately targeted children.

New York Governor Andrew Cuomo announced a ban on all flavored e-cigarettes besides tobacco and menthol in response to a recent nationwide spate of sometimes deadly lung illnesses that U.S. health officials have linked to vaping.