More questions remain after a pungent smell of gas along the L line has been making some MTA customers feel sick for a few days now.

The Transport Workers Union spoke out against what they are calling unsafe and unacceptable conditions Thursday. It is due to the smell that many workers have to endure all day long.

Yesterday, MTA safety officials say they are not sure exactly what the substance is or where it came from, but that it is a kind of heating oil that seeped up onto the tracks. They added that the material is not dangerous and are using absorbent materials and fans to get rid of the scent.

Despite the MTA's efforts, TWU officials have gotten many reports of workers feeling sick.

"We have four people who were treated and are out on what is called lost time, but overall we have about 15 people who were exposed during this two or three day process," says Lynwood Whichard, of TWU Local 100.

When reports of the smell first began Tuesday, the MTA even partially suspended service to investigate.