Timing belt replacement problem

Hi, I had my timing belt replaced on my 1996 Honda CRV about a year ago. When I picked up the car from the service department, I started the car and it blew a bunch of white smoke out of the exhaust. I drove it around the corner and the white smoke stopped coming out. I thought everything was ok. (The car never smoked before the timing belt change). Now when I sit at a redlight for more than a minute, white smoke blows out the exhaust. Is there something the service department did wrong when they replaced my timing belt? Thanks. Ryan