Buick Century 2005 gas smell

It may be a return or vent line , the lines may run just below the steering column like on a lesabre , see if they are wet , You should have any fuel leaks fixed ASAP

When I had this problem there was a relief valve under the hood that had to be replaced. It didnt spray all the time but when it did there was a strong smell. I finally had the hood up for something else and it popped and started spraying so I could see it. The mechanic claimed the relief was a common problem on the 2005.