La Mancha Negra (The Black Stain) is a mysterious black substance that has oozed from roads in Caracas, Venezuela which first appeared in 1986. Since the appearance of La Mancha Negra, it has caused multiple car accidents and claimed thousands of lives. Finding the cause of the substance has proven difficult and there are still no definitive explanations.
Contents
History
In 1986, La Mancha Negra first appeared as a smudge 50 yards long, it was noticed by workers as they patched the 30-year-old asphalt on a highway between Caracas and its airport. Initially, concerns for the blob were low but soon it spread. 100 meters, a mile, soon 8 miles of highway were covered with an unknown material that contracted and expanded with the weather. It grew when conditions were hot and wet but shrunk when it was cold and dry. It seemed to prefer tunnels and the uphill slopes outside the airport. Despite its gummy texture, the blob rendered the roadway extraordinarily unsafe, causing vehicles to crash into one another or run off the road. In 1991, a group of experts consulted President Carlos Andrés Pérez about the problem but could not pinpoint the cause of the substance. 1,800 deaths were then attributed to La Mancha Negra in the five years before 1992.
The Venezuelan government stepped in, stating that it devoted "millions of dollars" to investigating the problem, even consulting experts in the U.S., Canada, and Europe. In 1994, the Ministry of Transport and Communications attempted to wash away La Mancha Negra believing it was paste consisting of oil and dust and even suspended work when it rained believing it would wash away the substance. They tried spraying the stain away with pressurized water, but this did not work. They tried scrubbing it away with detergents to no avail. They even repeatedly scraped away the top layer of the roads, resurfacing it, only to watch La Mancha Negra reappear. Finally, the government poured tons of pulverized limestone over the stain to 'dry it up'. This seemed to work for a while, but created a different problem; the roads then became so dusty that drivers and local residents complained that the air was unbreathable.
In January 1996, the lack of maintenance, low rainfall and the poor quality of vehicles in Caracas made the roads slick with the substance once more. La Mancha Negra was thought to have been dealt with in 1996 after special cleaning equipment was brought from Germany. However, La Mancha Negra reappeared in 2001 on Baralt, Nueva Granada, Fuerzas Armadas, Sucre and Urdaneta Avenues in Caracas.
Composition
La Mancha Negra has been described as a greasy, black, thick blob that has the consistency of chewed bubble gum, though Venezuelans describe the roads it covers as "slick as ice". A team of the Venezuelan Ministry of Transport and Communications believed La Mancha Negra was composed of dust, oil, and various organic and synthetic materials.
Causes
Various theories have been put forward to explain the phenomenon, but no one has established its exact nature. One theory was that La Mancha Negra is oil that's seeping from sub-standard asphalt, with Venezuelans believing someone laid flawed asphalt that would leak oil when temperatures rose. However, the Ministry of Transport and Communications stated that the composition of the asphalt did not have anything to do with the formation of the substance. Others believe that it was the result of countless leaky, old cars spraying their fluids over the roadway. Professor Giannetto, a commissioner of the Ministry of Transport and Communications, believed that La Mancha Negra was an accumulation of dust on the roads and oil released from cars that formed a paste on the roads.
Finally, some believed that raw sewage from nearby slums was running downhill, under the asphalt, and causing a chemical reaction that broke the roads down. Venezuelan engineer and official Fernando Martinez Móttola stated in 1991 that he would not only remove the La Mancha Negra but also the residents near the Caracas-La Guaira highway since "they were part of the problem by creating leaks in the road".