The allegation comes in a lawsuit filed by the one-time finance executive who was fired by the vaping giant earlier this year. The lawsuit claims Juul fired the executive for protesting company practices, including shipping the tainted products.

Juul is the best-selling e-cigarette brand in the U.S., marketing several flavored nicotine solutions for use with its battery-powered device. The company is under siege from federal and state regulators amid an explosion of underage vaping.

A company spokesman said Wednesday the allegations that Juul shipped tainted product are “baseless.” The spokesman said the executive was fired because he failed to meet expectations for the job.

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