Drivers out in the early morning hours of New Year's Day were met with dense fog mixed with firework smoke, creating some dangerous conditions on the road.
In the San Leon community and Texas City area, police say seven vehicles were involved in a multi-vehicle pileup on Highway 146.
Authorities say it all started with a crash reported around 2:15 a.m. Within minutes, three more vehicles crashed in the same area.
One SUV ended up in a ditch as the driver tried to avoid the other collisions.
No one was seriously injured or taken to the hospital.
Police called the nearby Bacliff and San Leon Fire Departments to bring out fire engines and lights to alert drivers headed in the direction of the crash scene.
Officials said the fog was so thick at one point, visibility was less than a couple feet.
Elsewhere, ABC13 viewers sent in several videos and photos overnight of what it looked like in areas such as Highway 290 and Mueschke, Garth Road and Spring Park Drive, and Scarsdale and Beamer.
One viewer reported zero visibility in east Harris County. It was also difficult for some drivers to see in Spring around the Rayford and Highway 99 area.
ABC13 meteorologist Travis Herzog says the smoke from fireworks was trapped near the ground due to a strong temperature inversion (very stable air). Travis explains that the smoke particles are worsening what would otherwise be a fairly benign round of fog. He says we were expecting fog, but it was worsened by the amount of fireworks set off overnight.
Travis adds this is the worst air quality he's seen over the city as measured by the local pollution sensors.