Rescue workers stopped their search for the remains of 63 miners killed in a mine blast a year ago.
Industrial Minera Mexico spokesman Oscar Kaufmann said the company gave Coahuila state authorities a report by a U.S. mining expert that found the mine is dangerously contaminated and continuing the search would endanger more lives.
"We're waiting to hear from authorities before deciding whether the search will be called off," Kaufmann said.
In leaked excerpts of a report published Monday in several local newspapers, Daniel G. Wooton, vice president of operations for Kentucky-based Phoenix Coal Corp. and a former president of the Illinois Mining Institute, wrote that waters tainted by human remains have flooded much of the mine.
"Depending on the health of the victims, rescue workers may be exposed to chronic infectious hazards including hepatitis, HIV, enteric pathogens and tuberculosis," Wooton wrote in his report for the company. "This exposure could pose a severe health risk not only to mine personnel but also to their families and, ultimately, the entire community."
The report also found the mine still contains large amounts of toxic gas and is unstable in many places.
The Feb. 19, 2006, explosion at the Pasta de Conchos mine in northern Coahuila state sparked temperatures reaching 1,110 degrees Fahrenheit (600 Celsius). Rescuers have found the bodies of two miners and explored about a third of the mine, but toxic gases and tons of wood, rock and metal debris have hampered recovery efforts.
Industrial Minera Mexico is owned by Grupo Mexico SA de CV, a railroad and mining giant with operations in Mexico, Peru and the United States.
Grupo Mexico has insisted the mine met all safety standards and denies allegations that safety precautions were ignored.
A judge last month ordered five mine officials to stand trial on negligent homicide charges.
The company does not plan to reopen the mine once recovery efforts conclude