In late December, Unit 2 of San Juan Generating Station tripped off because of a potential boiler problem, leaving utility owner PNM faced with a potential asbestos problem as well.
The coal-fired generating plant, which operates as four units (Unit 2 producing 1,800 megawatts of electricity, or enough to serve about a million homes), is owned by a consortium of utilities, with Unit 2 under the joint ownership of PNM and Tucson Electric Company. PNM manages the facility, which produces more than half of the electricity PNM delivers during an average Southwest summer.
Built in 1973, at the end of an era in which asbestos was considered the paradigm in providing high insulative values for thermally demanding equipment, San Juan’s boilers and plant piping present a huge risk of asbestos exposure.
Some of this asbestos insulation was exposed when the Unit 2 problem occurred, according to PNM spokeswoman Susan Sponar, who was quick to point out that the episode did not involve an explosion, which would have spread the asbestos risk across the entire plant.
Asbestos, widely and extensively used in and around high-heat machinery like boilers, boiler pipes, furnaces, heating equipment, ductwork, and combustion chambers in wood and oil stoves, is a naturally-occurring silicate-type mineral that emits microscopic fibers when broken or disturbed.
By 1960, health officials and others had begun to recognize asbestos’ dangers, recognizing that the link between asbestos exposure and mesothelioma, a form of cancer, was becoming very clear. The end of that decade saw asbestos use gradually reduced by mutual agreement between health professionals and manufacturers, and in 1989 the U.S. Environmental Protection Agency limited it to one percent of less (by weight or volume) in domestically-manufactured products.
However, the legacy of malignant mesothelioma, which lies dormant for up to five decades before producing symptoms of enough severity to force patients to see a doctor, will not lessen before 2030. Until then, 2,000 Americans per year are expected to be diagnosed with this dread form of cancer, and most of them will receive a prognosis of one year, or perhaps slightly more, to live.
The San Juan power station, which has undergone several upgrades – not only to pollution control and emissions equipment, but to the asbestos in the plant – remains one of the most polluting power plants in the nation, earning a spot on the nation’s list of the “Dirty Thirty” power plants.
Once the incident cause was assessed, PNM officials acted quickly to limit asbestos exposure via various measures, including closing the plant, sampling the air, and sampling the material, which was reportedly shown not to contain asbestos.
While the plant remains closed, in what is being handled as a scheduled outage, Units 1, 3 and 4 continue to operate, providing electricity to area residents. Some of the plant’s 400 workers, returning to Unit 2 now that there is no danger, will make needed repairs once the scope of the problem is determined. No word has been given on the probable date of completion.
Source: Farmington Daily Times