For Texas border communities and independent bridge owners, a U.S. withdrawal from the North American Free Trade Agreement could turn back time to the days when the U.S. Mexico border corridor suffered grave economic conditions.

If a withdrawal from the NAFTA agreement actually happens, many say local and business economies will greatly suffer, and companies and their investors who have spent millions in building bridges, refrigerated warehouses and trucking infrastructure would be forced into what some are calling a fatal economic tailspin that could eventually lead to bankruptcy.

Even cities and communities like Mission, McAllen, Harlingen, Brownsville, Laredo, Del Rio and other Texas border communities, would feel the sting. Community leaders, business owners, state legislators, and even Texas Governor Greg Abbott have warned of economic consequences if NAFTA is not successfully renegotiated.

"Gov. Abbott believes we need good, fair trade deals that will benefit the United States and its workers," said John Wittman, a spokesman for the Governor's office.

Though Abbott, like many Texans, support Trump's economic policies in general, Whitman was quick to add that Mexico is Texas' largest trading partner, noting that Texas sends more exports south of the border than any other state. Goods shipped across border land ports generate an estimated $178 million annually to Texas businesses.

Related:Little progress in NAFTA talks, Texas business leader warns Texas could be hurt the most

KEY BRIDGE

The Pharr-Reynosa International Bridge, completed and opened in 1996, serves as one of the most important ports of entry for the U.S./Mexico border. It handles both commercial and passenger operated vehicles and crosses about 175,000 vehicles each month. It is the No.1 bridge in the country with respect to the crossing of fruits and vegetables — an impressive 60 percent of all produce shipped into the U.S. from Mexico via land ports.

While the Pharr-Reynosa Bridge is only one of about nine major international bridges that connect Texas with Mexico, the average monthly revenue for commercial trucks crossing the Pharr Bridge is nearly $1 million, according to Texas records.

But the greater loss of revenue for communities and businesses in the border corridor would be the support industry that makes border shipments possible in Texas, such as warehouses, including massive and independently owned refrigerated warehouses, banks, money exchanges, oil companies that benefit from fuel service, trucking companies, truck stops, mechanic shops, many retail and grocer outlets, and taxing entities like city, county and state governments.

PRIVATE BRIDGE OWNERS

Sam Vale is a second generation bridge owner who operates a two-lane crossing in Rio Grande City in the Texas Valley of deep South Texas. Vale charges each commercial truck that uses the bridge $30, creating millions in revenue each year for his operation.

A little farther south on the border, Sam Sparks, Jr., is a private bridge owner, along with his siblings who operate a four-lane crossing connecting Texas with the Mexican border town of Progreso. While produce represents the bulk of shipments across Texas land ports, Sparks' bridge primarily is used for shipping grain from the U.S. into Mexico. For the shipment of U.S. corn headed into Mexico, Sparks' bridge represents one of the busiest land ports in the nation used to truck grain into Mexico.

Sparks, like Vale, charges $30 a truck for crossing the bridge in either direction, and he says the revenue has helped his bridge business generate multi-millions over the years.

 STORAGE FACILITIES AT RISK

Also at risk are over 20 super-sized refrigerated cold storage facilities located in Texas, many of them solely dedicated to storing fresh produce and other food items from Mexico that eventually make their way to points north and east of Texas and to distant locations in the Midwest and East Coast. Warehouse officials report they have invested heavily through the years, especially in more recent years, to construct these massive storage facilities, which rely heavily on storage for food products that have crossed the international border as a result of NAFTA.

And it's not just produce and food products that rely on NAFTA traffic to keep their businesses profitable and their doors open. Major retailers and manufacturers are making their voices heard to keep the trade agreement alive. The New York Times reported last week that a coalition of U.S. businesses has protested rules that could make it more expensive to bring parts and products in from Mexico if NAFTA negotiations fail.

While land ports are used extensively to ship goods across the border in both directions, about $373 billion in cargo by truck last year according to the American Trucking Association, other goods from and to Mexico travel by ship, rail and even air to a lesser extent. Rail and oceanic shipping industries would also suffer if Trump decides to withdraw from NAFTA.

Sparks says he voted for Trump in the last general election, but admits he and others who rely on NAFTA want the administration to "lay off" when it comes to the 34-year trade agreement. To do otherwise, he says, could spell disaster for his and many other businesses that rely on trade with Mexico and Canada.