HOUSTON (Reuters) - One barge was severely damaged and another capsized following a collision with a 755-foot (230-m) tanker in the Houston Ship Channel near Bayport, Texas, that spilled about 9,000 barrels of gasoline into the waterway, officials said.

No injuries were reported. Salvage teams were at the site on Saturday, U.S. Coast Guard officials said.

It was the second spill in two months to affect traffic on the 53-mile (85-km) commercial waterway that connects Houston to the Gulf of Mexico. Nine U.S. oil refineries that process 12 percent of the national total operate along the ship channel.

Air monitoring systems have detected no “above actionable levels” of pollution, said Bayport Channel Collision Response, a group of federal, state and shipping officials organized to clear the wreckage and deal with the spill.

Emergency responders placed more than 3,800 feet of floating boom lines as of Saturday morning and were planning to lay another 12,150 feet around the barges and sensitive areas along the nearby bay, the group said.

There were 33 vessels waiting to move inbound and 27 waiting to exit on Saturday afternoon, the group said Saturday afternoon, with 91 vessels at anchor.

The collision, between tanker Genesis River and a Kirby Inland Marine tug towing two barges, halted all traffic between lights 61 and 75, the U.S. Coast Guard said. It reopened a portion of the channel to one-way traffic between light 66 and 67 on Saturday afternoon.

A safety zone also was set up that expanded shipping restrictions to light 66 and up to but not including the Bayport Ship Channel, officials said.

Each of the two barges were carrying about 25,000 barrels of a gasoline blend stock called reformate.

In March, a fire at a petrochemical tank farm along the waterway burned for days, sending black smoke into the air and spilling fuel and solvent into the channel, disrupting ship traffic for weeks. Hundreds of people reported respiratory and other ailments at clinics set up to provide medical aid after the fire.

(This story corrects volume of gasoline to barrels from gallons in paragraphs 1 and 9.)