WASHINGTON – Passing a new farm bill in Congress is being threatened again but this time, it is over California egg standards.

Rep. Steve King, R-Iowa, has included an amendment known as the Protect Interstate Commerce Act in the House farm bill that would prevent “interference by state and local governments with production or manufacture of items in other states.”

California passed Prop 2 in 2010, which states egg imports must be produced in an environment that allows hens to spread their wings. This standard is one of many that would be nullified if King’s provision makes it into the final farm bill.

The amendment raises the contentious question of how much sway one state’s rules should have on another state’s ability to sell its agricultural goods beyond its borders. This is a particularly poignant issue for Iowa’s egg industry.

Iowa exported approximately 94.6 percent of its eggs in 2012. Approximately 2.7 million 30 dozen cases of Iowa eggs went to California in 2008, which is the most recent data available.

“2012 numbers would be similar since flock sizes in the major states didn’t change much in the last five years,” said agricultural economist Maro Ibarburu at Iowa State University’s Egg Industry Center.

Hillcrest Farms in Cedar Falls, Iowa, is a small family egg producer selling mostly to private customers and some markets. However, if it had to abide by California’s stricter regulations to sell it that populous state, owner Jack Darland, Jr. would rather get out of the egg business.

“Eggs are pretty low maintenance and one of the few things on the farm that are profitable. If we were told we need to change things about production, then we sell the chickens,” said Darland, Jr.

According to the U.S. Department of Agriculture, Iowa leads the U.S. in egg production with 1.26 billion eggs being produced in 2012, an increase of two percent from the prior year.

“All of this uncertainty in the marketplace is paralyzing and has a detrimental impact on capital investment and job creation,” said Rand Fisher, president of business consulting firm Iowa Area Development Group. “Iowa is No. 1 is egg production and processing with over 60 million laying hens in the state.”

Changes in production standards would have a negative effect on Iowa egg exports and, according to the advocacy group Egg Farmers of America, the King amendment would aid trade between states.

King’s provision would “end the trade barriers enacted by some states. Production practices by farmers are best left to the farmers to ensure safe and wholesome agricultural products are produced for the nation’s consumers,” said Ken Klippen, a consultant for the advocacy group.

But industry experts and lawmakers worry the language of the amendment leaves too much to be debated.

“The King amendment is vague and its precise meaning is difficult to pin down,” said Dale Stern, partner at law firm Downey Brand LLP. “It has the potential to wipe out delicately balanced and long-standing state agriculture programs.”

A total of 151 Democrats and 16 Republicans have signed letters maintaining that King’s provision would upset nearly 150 state laws, most notably California’s Proposition 2, which goes into effect in 2015.

“No sector of agriculture – from eggs to milk to vegetable crops – is safe from the King amendment,” Stern warned.

Under King’s amendment, out-of-state importers would not have to abide by California’s Prop 2, driving prices down as result of the lower cost of production. But California farmers still would have to follow the provisions of Prop 2 as a state law.

“This bill threatens the ability of every state to protect consumers and animals and would put California egg farmers out of business,” said California State Rep. Jared Huffman, D-San Rafael.

In order to pass a final farm bill, congressional negotiators will work to rectify differences between the House and Senate bills before the current farm law expires Sept 30.