My machine has been idle (stored) for about 3 years as my new home was not outfitted with gas. Recently gas service was installed along with a new gas furnace so I had additional pipe run for dryer. All seals have been checked but inside dryer is nat gas odor when turned on. What should I do? Thx.

When it was running, was the flame on? Can you take the cover off the front and look?
Maybe 3 years of dust/dirt/etc clogged various places of the burner and it needs cleaning.
Of course you want to be careful and to have someone standing by to shut it off if you are on the floor looking. It's probably not dangerous though.

Don't fool around with gas. If you can't ID the source, call your gas company, they will find the source but not repair.

You need to rear it down and clean it. Then if you smell gas call someone to check it out. You can check the gas connections with soap bubbles, but you should not take any risks. Have an expert check it out. Here are some manuals: https://dl.dropboxusercontent.com/u/8010163/Whirlpool_Duet%20Job%20Aid.pdf
https://dl.dropboxusercontent.com/u/8010163/Whirlpool%20L-79%20Duet%20Sport%20Dryer%20Service%20Manual.pdf