Update 11:31 p.m.: The Delaware Memorial Bridge reopened after a release of toxic gas forced its closure for about six hours on Sunday.

Croda Inc., who owns the plant where the gas leak occurred, said it had been completely contained.

"We can confirm that the situation is now under control, as the ethylene oxide release is fully contained," the statement read.

- - - - -

A vital interstate bridge in South Jersey has been shut down on one of the busiest travel days of the year.

Delaware River and Bay Authority spokesman James Salmon said the Delaware Memorial Bridge was shut down around 5 p.m. due to a chemical gas leak at the nearby Croda production plant in New Castle, Delaware. The plant is located next to the bridge's northbound suspension.

Croda said in a statement the chemical released was ethylene oxide, a flammable and reactive gas used primarily in industrial chemicals. Exposure to the gas can cause serious health problems, according to the federal government.

"There are no injuries to report, but as a precaution highway traffic near the site was stopped," Croda's Marketing Director, Cara Eaton, said in a statement. "We are working to resolve the issue as quickly as possible to minimize further community impact."

Eaton said the company is investigating what caused the release of the gas.

Salmon says DRBA was notified to close down the bridge and to redirect traffic by the Delaware Department of Natural Resources and Environmental Control (DNREC).

Salmon added DNREC officials are currently on site at the plant and there is no estimate as to when the bridge will reopen. Fire officials from New Jersey and New Castle County, Delaware are assisting with the situation.

As of 9:30 p.m., delays were spilling into nearby throughways. The New Jersey Turnpike was closed to traffic at exit 2, and delays were reported along Interstate 295 leading to the Commodore Barry Bridge, the next nearest crossing of the Delaware River, according to 511NJ.org.

The toll plaza, which would be jammed by vehicles on a holiday weekend, is empty of vehicles Sunday night after the Delaware Memorial Bridge was shut down in both directions

The bridge handles up to 75,000 vehicles in the southbound direction daily and with Sunday being one of the busiest travel days of the year, the number of vehicles doubles.

It is the only bridge in Delaware that connects to New Jersey, and is primarily used by travelers coming from 95 to the state. It also feeds into the New Jersey Turnpike and I-295.

Chris Franklin can be reached at cfranklin@njadvancemedia.com. Follow him on Twitter @cfranklinnews. Find NJ.com on Facebook. Have a tip? Tell us. nj.com/tips

Bill Gallo may be reached at bgallo@njadvancemedia.com. Follow Bill Gallo on Twitter @bgallojr. Find NJ.com on Facebook.