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New York City’s subway riders are used to a spectrum of smells, most of them unpleasant.

But the mysterious fumes that have permeated the L train this week and made some subway riders and transit workers feel ill, go beyond the usual odors a New Yorker endures.

On Tuesday, the Metropolitan Transportation Authority suspended service for two and a half hours to investigate harsh fuel smells at the Graham Avenue stop in Williamsburg, Brooklyn. On Thursday, subway riders and transit workers said the odor, a dizzying chemical stench that forced some to breathe through tissues over their faces, continued to linger.

Amie Roe, 34, who is eight months pregnant, said the smell hit her especially hard on Tuesday. “It was really intense,” she said, swaying side-to-side to pantomime her dizziness.