In the first two months of 2005, the government-run company, known as Pemex, was fined $170,000 for 17 different instances of non-compliance with environmental laws and forced to close three plants.
According to a report from the federal environmental agency Semarnat, the environment-related fines against Pemex represent twice the average amount other Mexican industries have received.
The report also noted only 20 percent of Pemex's facilities were in 100 percent compliance with federal environmental protection laws during the past five years.
In January, liquid gas from Pemex pipelines leaked into two rivers and contaminated coastal communities in the eastern Mexican state of Veracruz, where many of Pemex's operations are based.
After the spills occurred, the company's chief executive, Luis Ramírez, said Pemex would double its efforts to ensure its production is clean and safe.