Runaway barges dealt a devastating blow Friday to a key freeway crossing of the San Jacinto River, which will delay drivers and maritime traffic for at least the next few days.

At least two barges slammed into the Interstate 10 bridge crossing the river around midnight, as nine nearby barges came loose from their holding spot a quarter-mile north of the span. The cause remains unclear.

Six barges made it past the bridge and have been corralled, said Cmdr. Nicole Rodriguez, on-scene coordinator for the U.S. Coast Guard, which is working with state and local officials on the incident. One barge was grounded along the San Jacinto Waste Pits Superfund Site.

The other two remained pinned to the columns of the bridge, with the swift current making it impossible to move them.

“They have all been looked at,” Rodriguez said. “There is minimal damage to all nine barges.”

No public health issues are apparent, she said, but officials are monitoring air and water quality in the area because of the hydrocarbons contained on the barges.

Only after the barges are removed can the safety of the eastbound and westbound bridges — each direction of the freeway is a separate span — be assessed, said Emily Black, spokeswoman for the Texas Department of Transportation.

Both directions of I-10 will remain closed until they can be deemed safe, Black said. That process that could take days as crews wait for the current to weaken, water levels to drop and divers to look at the structural integrity of the columns supporting the bridges.

“There is clear damage we can see before we even get our inspection crews there,” Black said. “You can see the areas where the barge hit the bridge.”

Officials are directing most traffic around the closing via U.S. 90 and FM 2100, north of I-10. Harris County Toll Road Authority is waiving tolls on the eastern Sam Houston Tollway to ease traffic moving to and from I-10 to U.S. 90.

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From an initial assessment, it appeared the westbound span, which is upstream, took the bulk of the impact, Black said. Should the early appraisal hold that the eastbound side received minimal damage, she said officials could shift westbound traffic to share the eastbound span, in the event significant repairs are needed.

“We are going to be working as quickly as possible, but there are some answers we do not have yet,” Black said.

The cause of the breakaway barges remains under review. Joe Tyson, senior vice president of Canal Barge Company, which owns the vessels, said the company is cooperating fully. A vendor that oversees the mooring of the barges together did take normal precautions during Imelda’s deluge, he said, including using two lines to affix the barges.

The three barges that remain an issue were carrying a variety of chemical cargoes, according to the Environmental Protection Agency. One that hit the bridge was carrying 17,000 barrels of monoethylene glycol, a component used in antifreeze. The other was loaded with 10,000 barrels of naphtha, a highly-flammable hydrocarbon compound used for solvents and the production of gasoline.

A third barge carrying 10,000 barrels of lube oil grounded on the northeast corner of the San Jacinto Waste Pits site, the EPA said in a statement. Officials are coordinating with the Superfund site overseers to remove the barge.

Frustrating Delay

For some drivers, the closing Friday caused a time-sucking detour as TxDOT and police directed eastbound vehicles off at Magnolia and westbound vehicles at Crosby-Lynchburg.

For residents such as Michael Moreau, 59, the freeway closure following heavy rains was not much of a surprise, even if it was sure to be a headache.

“It causes a lot of inconvenience for the commuters here,” said Moreau who was on a bike ride in the area.

It is a familiar inconvenience for some. In February, a barge struck columns of the bridge leading to a partial shutdown of the bridge for nearly three months.

During major storms in the Houston, it is not uncommon for a barge to come loose from its moorings. Often, debris and surging waters stress ropes used to lash barges together, or simply elevate the boats above the docks to which they are affixed.

In the aftermath of Harvey, a barge knocked loose by a flooded San Bernard River ripped into a dock and boathouse.

Moreau said he did not think the I-10 bridge was built high enough and needed to be redesigned.

TxDOT does not have long-range plans to replace the bridge, but has an upcoming project to add more bumpers around the columns of the bridge. Bumpers cannot avoid damage, but can work to minimize them. Black said the work to add bumpers is not imminent, but planned.

“Anytime there is a recurring issue we are going to look and see if there is something we can do,” Black said.

Often, the agency is pressed into action by calamity when it comes to bridges. Along Intersate 45 in downtown Houston, officials frequently were forced to address minor damage to the Dallas Street bridge, which had one of the lowest bridge heights in the region. Eventually, the span was dealt a crippling blow by a truck carrying a piece of a construction equipment on a trailer three years ago, and was replaced as part of an emergency construction project.

Reporters Perla Trevizo, Michelle Iracheta and Brooke Lewis contributed to this story.

dug.begley@chron.com