Updated

Spain and the United States have reached an agreement to clean up radioactivity in the Spanish farming village of Palomares, on Spain's southeast tip, 40 years after two U.S atomic bombs fell in the area after a midair collision, news reports said on Sunday.

The agreement to clean the area was reached at a meeting mid-September between the U.S. Department of Energy and Spain's CIEMAT, the national Center for Energy and Environment Investigation, leading Madrid daily El Pais reported.

The accident took place on the morning of Jan. 17, 1966, when a B-52 bomber collided with a flying tanker while refueling over Palomeras and released all four of its hydrogen bombs in the ensuing explosion.

CountryWatch: Spain

The high-explosive igniters on two bombs detonated on impact, spreading radioactive material, including plutonium, over a wide area of the Spanish countryside. A third bomb landed relatively intact and was recovered.

The fourth bomb landed in the Mediterranean Sea, and U.S. military searchers took months to find and recover the device intact.

Seven of the 11 crewmen aboard the two planes were killed in the collision. There were no fatalities on the ground.

The agreement states that the countries will jointly pay for the costs and that the works could take years depending on the levels of radioactivity found, El Pais added.

"Not even the Americans know what is there. There could be nothing, but there could be a problem and if there is, it will be solved," CIEMAT's General Director Juan Antonio Rubio is quoted as saying in El Pais.

Calls to CIEMAT were unanswered Sunday.

New scientific studies have traced the spread of radiation from the accident site.

In 2001 CIEMAT detected higher levels of plutonium, uranium and americium than average over 24 acres of Palomares.

At the time of the collision, villagers, who earned their living mostly by fishing and farming, feared the plutonium radiation might have contaminated not only their bodies but also the waters they fished and the soil they farmed.

But in 1966, Spain was under the thumb of Gen. Francisco Franco and very little information about the accident was officially released. In order to minimize the consequences of the accident, Spain's Information and Tourism Minister Manuel Fraga and U.S. Ambassador Angier Biddle Duke strode into the Mediterranean near Palomares to demonstrate findings indicating that the waters were safe.