BURNING OUR HEALTH: HAZARDOUS WASTE INCINERATION IN CEMENT KILNS IN MEXICO
In the search to be more commercially competitive, the
cement industry in Mexico is burning hazardous wastes as "alternative
fuel" in their cement kilns, attempting in the process to reduce the
cost of more traditional fuels, like coal, fuel oils or natural gas. This
strategy is promoted by a group of foreign companies that have made hazardous
waste "recycling" a big business and found acceptance by Mexico's
environmental authorities. The industry argues that energy recycling of
wastes is ecological because it saves fossil fuels and natural
resources; nonetheless, the experience internationally with this practice
shows that it is a dirty technology which should not be transferred to
Cement Production and Conventional Environmental Problems
Traditional cement production can cause environmental problems: the continual extraction and mining of limestone and other materials leaves large scars in the earth; inadequate transportation of extracted materials for grinding and storage in the plant produces a tremendous amount of dust. As in any combustion process, the calcination process in the kiln produces air pollutants, including carbon monoxide, sulfur dioxide, nitrogen oxides and particulate matter. The amount depends on the type of fuel, air pollution control equipment and parameters of the kiln's operation. The left-over cement kiln dust can be contaminated with heavy metals and other pollutants. If the cement kiln dust is deposited back in the quarries from which the limestone was extracted, or to a municipal landfill, it can contaminate soils, groundwater and flood waters.
Exposure to carbon monoxide negatively impacts the central nervous system and, along with nitrogen oxides, sulfur dioxide and suspended particulate matter, irritates the lung tissue and the respiratory system and aggravates the symptoms of people with lung diseases (asthma, chronic bronchitis). Exposure to these contaminants can also increase cardiac and other circulatory problems as well as acute respiratory sicknesses.
How is cement produced?
Cement is produced through a five-step process:
A) It begins with the extraction of its prime materials, principally limestone (70%), but also other materials like clay, aluminum oxide, iron, shale and silica. B) The materials are ground and stored separately. C) The material is measured to achieve a specific combination, depending upon the type of cement desired, and ground to produce a very fine powder. D) The powder is pumped to silos, where the blend is standardized before being placed in long, rotating kilns, where the material is calcinated at high temperatures (approximately 1,500 degrees centigrade), causing chemical and physical reactions. A new material is formed, which is called pre-cement or more commonly clinker, which are composed of small balls about the size of a nut. E) Finally, the clinker is ground up, combined with gypsum and packaged. When this product -- cement -- is mixed with sand, stone, other materials and water, concrete is produced.
The calcination process, turning the limestone into clinker in the kiln, is the fundamental step described above. This process requires a substantial amount of energy, provided by the burning of fuels, which are injected at the opposite end of the kiln, and it represents the major economic cost in cement production.
What environmental problems and health effects can happen when hazardous waste is used as the fuel in the cement-making process?
*The amount and types of air contaminants -- including carbon monoxide,
sulfur dioxide, nitrogen oxides and particulate matter -- increase, more so
than with the burning of coal, petroleum or natural gas.
The exposure to heavy metals can provoke serious health effects. The exposure of a pregnant woman to lead can cause development problems in the fetus and affect the neurological development of the child, including its future intelligence; exposure to cadmium can affect the kidney, liver and lungs, cause genetic damage and has been proven to cause cancer in rats; mercury exposure at high concentrations can cause permanent damage to the brain, the kidneys and to fetuses in development; the nervous system is especially sensitive to the effects of mercury, provoking more severe disorders with increases in exposures (irritability, nervousness, trembling, vision and hearing changes, memory problems). Other suspected or known carcinogens emitted by rotating kilns incude berilium and hexavalent chromium.
Contaminants generated in the incineration of hazardous wastes in cement kilns
Dioxins and furans are organic contaminants, created in the burning of hazardous wastes, which contain chlorine (commonly present, for example, in solvents and plastics) and have three main characteristics. First of all, they are extremely toxic, producing severe chronic effects, including cancer and endocrine system disruptions, and result in the loss of fertility, affect the immune system and alter the development of fetuses in human and animals. They are also very persistent: they have a half-life of 9 to 15 years in the soil. Finally, they bioaccumulate in the environment, concentrating in the fatty tissues, increasing their concentration as they move up the food chain, which means that the largest concentrations would be found in humans and eventually in children, passed through contaminated mother's milk.
In addition to the exposure of heavy metals and dioxins and other Products of Incomplete Combustion through inhalation -- not only by the cement plant workers but others in the surrounding community -- there are a number of other exposure paths. The pollutants can be carried by air currents and deposited on water and soil, where they are taken up by plant and crop roots, and then accumulate in fish and animals, including in beef, milk and eggs.
Which cement plants are burning hazardous wastes and what types of hazardous wastes are they burning?
According to 1996 informaiton, 21 cement plants out of a total of 29 plants in Mexico have provisional permits and temporary authorization to burn hazardous wastes in their kilns. Leading the practice are Cementos Mexicanos (CEMEX), which has permission in 11 of its plants, and Cementos Apasco, with 6 plants authorized to burn hazardous wastes. In addition, Cooperativa Cruz Azul (2 plants) and Cementos Portland Moctezuma and Cementos de Chihuahua (one plant each) also have permission to burn hazardous wastes. Currently, CEMEX is burning hazardous wastes in 5 of its plants; Cementos Apasco in all 6; Cruz Azul in both its plants and Cementos Portland Moctezuma in its one plant. About 70,000 tons of hazardous wastes and alternative fuels were burned in cement kilns in Mexico in 1997, according to representatives from the cement industry.
The hazardous wastes permitted to be used as alternative fuels include solid wastes, such as tires, battery shells, contaminated soils and sludges. Liquid hazardous wastes, which form the majority of the waste burned, include solvents, grease and used oils, refinery waste and distillation sludges.
The hazardous waste fuel-blending facilities that produce these
alternative fuels have identified 112 different liquid, semisolid and solid
hazardous waste streams with combustion (energy) value. These are principally
waste streams of the automobile, chemical, electronics, paint manufacturing
and petroleum refining industries. The types of blended wastes include oils
and grease by-products of petroleum waste and distillation tanks, paint
wastes and subproducts, used solvents, used chemicals, as well as
contaminated papers, rags, cardboard, filters and other products.
Mexican Cement plants with temporary authorization for burning hazardous wastes as alternative fuels
What commercial interests are promoting the incineration of hazardous wastes in cement kilns?
Transnational companies, principally from the U.S., have conducted joint ventures with the largest cement industries in Mexico to create a new industry which provides a collection and blending of hazardous waste service to the cement kilns, locating fuel-blending plants next to the cement industry.
The environmental authorities provided permission to Pro Ambiente for the installation and operation of a waste fuel-blending facility on land owned by CEMEX at its Torreón, Coahuila plant, which can substitute up to 40% of traditional fuel oils with which it normally produces cement. The plant was partially financed by Mobley Environmental Services, a U.S. company. Similarly, Cementos Apasco has a joint venture with Waste Management Inc. (formerly Chemical Waste Management) and built a fuel-blending facility, known as Ecoltec, at its plant in Ramos Arizpe, Coahuila. Finally, a waste fuel-blending facility called BFI Química Omega, owned by BFI, the gigantic U.S. waste management company, as well as by a Mexican subsidiary of Metalclad, provides "alternative fuels" to several cement plants within Mexico.
Industries designed to collect and blend hazardous wastes for their use as alternative fuels in cement kilns
The hazardous waste recycling business increasingly includes waste from both the U.S. and Mexico and has become more binational in character. Mexico's main environmental law, the LGEEPA, permits the import of hazardous wastes for recycling (Article 153), potentially allowing waste to be imported to Mexico for incineration in cement kilns.
U.S. companies are expanding their investments in the hazardous waste disposal and recycling market, forming a powerful influence on public policy related to hazardous waste management and taking advantage of the North American Free Trade Agreement (NAFTA) and the pro-business philosophy of the Mexican government. In this way, a dirty technology which has met with fierce opposition in its country of origin is being transferred to Mexico.
On the border between the U.S. and Mexico, Ford Environmental Services
(Servicios Ambientales Ford) is promoting a financing proposal to the Border
Environment Cooperation Commission and North American Development Bank to
establish a hazardous waste fuel-blending facility in Ciudad Juárez,
Chihuahua (across from El Paso, Texas). This plant would offer these blended
hazardous wastes as fuel to the cement industry on both sides of the border,
thus competing for the emerging market of hazardous wastes produced by the
What have Mexico's environmental authorities done about this problem?
The federal environmental authorities from the National Ecology Institute (INE) have been authorizing temporary permits to allow cement plants to burn hazardous wastes for the last three years. These provisional permits are based on test burns, which are reported twice a year to the authorities despite the lack of any official regulations governing the practice. Proposed rules yet to be adopted would establish maximum emission limits for heavy metals, PCBs, hydroflourines, hydrocarbons and a maximum chlorine content of 2% of the total wastes burned.
The problem with basing temporary permits on the test burn procedures is that these test burns do not always reflect the daily practice of the hazardous waste burned in real operating conditions and it is very difficult to monitor the hazardous waste used as fuel, the emissions from burning them and the wastes -- principally cement kiln dust -- generated. In the case of dioxins and furans, Mexico lacks the experience and equipment to accurately monitor and measure emission levels.
In March of 1996, SEMARNAP, the federal environmental agency of Mexico, represented by INE, signed an agreement with the National Chamber of Cement (which includes representatives from all the major cement companies) and Cooperativa Cruz Azul (Blue Cross Cooperative) to establish a program of alternative fuel energy recycling in cement kilns using industrial hazardous wastes.
The Integrated Hazardous Waste Management Program for Industrial and Hazardous Wastes in Mexico (1996 - 2000) includes waste blending and incineration of hazardous wastes in cement kilns as acceptable energy recycling practices and seeks to promote this practice in CIMARIs (Integrated Centers of Management and Treatment of Hazardous Wastes), which they propose locating throughout Mexico.
What opposition has the practice of incinerating hazardous wastes in cement kilns generated in other countries?
In the United States and Europe, the communities that have lived with cement plants burning hazardous waste have recognized the myths of ecological energy recycling and have organized themselves to defend their health and environment.
National health associations -- such as the American Lung Association -- have opposed burning hazardous wastes in cement kilns and have produced video testimonials about the health problems that this practice provokes in the local population.
Citizen organizations, with help from members of the U.S. Congress, have proposed an initiative to label cement as to whether or not it was produced with hazardous wastes, giving the consumer the option of choosing cement produced with a cleaner process.
Even the commercial hazardous waste incinerator industry has opposed the cement plants that burn hazardous wastes because of their unfair competitive advantage. The cement plants are able to burn hazardous wastes in the U.S. with much less restrictive environmental standards and will continue to enjoy an unfair advantage until stricter, more comparable standards are imposed and enforced.
In Mexico, more than 40 environmental and social organizations have asked the environmental and health authorities to cancel the authorizations and temporary permits granted to the cement plants in an open letter signed June 24, 1998.
Are there any alternatives?
The alternative to burning hazardous wastes in the making of cement is simple: require the use of less contaminating fuels such as fuel oils or the least contaminating alternative, natural gas.
The huge underutilization of natural gas produced by Pemex, the privatization of the delivery of natural gas in Mexico and the tendency toward price reductions offer greater opportunities for Mexican cement plants to take advantage of natural gas.
The cement industry is the key player in the construction sector, and some industries have shown themselves to be very competitive internationally, even operating outside of Mexico. Mexico's cement industry resources and innovative capacity should be focused on designing strategies to increase the efficiency and energy content of fuels, in the process rejecting the use of hazardous wastes. The industries should institute a program of reduction of hazardous wastes throughout the entire cement production-cycle.
What can you do?
*The right to know environmental information. Investigate in your municipality or state whether the cement plants are burning hazardous wastes as an alternative fuel, what types of waste and volumes they are burning, as well as the types and volume of emissions and waste they generate.
*Freedom of expression and protest. Express yourself through peaceful, public and active means. Oppose this practice and make the cement plants, municipal, state and federal environmental authorities and your political representative aware of your views. Express your comments when the official standard for thermal treatment of hazardous wastes is published in Mexico or when proposed standards in the U.S. are announced. Tell the Border Environment Cooperation Commission (BECC) and the North American Development Bank to reject any approval or financing of projects that promote the incineration of hazardous wastes in cement kilns. (BECC: PO Box 221648, El Paso, TX 79913; Tel: (011-52-16) 25-91-60; Fax: (011-52-16) 25-61-80).
*Communication and citizen solidarity. Establish relationships with national and international citizen groups which have already organized against this practice; discuss and adapt the resources, legal and political strategies to best address your particular cement kiln problem.
For more information:
You can ask for the complete report, entitled Incineración de Residuos Peligrosos en Hornos Cementeros en México: La Controversia y Los Hechos (Hazardous Waste Incineration in Cement Kilns in Mexico: The Controversy and The Facts), available only in Spanish, as well as a video produced by the American Lung Association, at:
COSYDDHAC: Calle 24, #3007, Col. Pacífico, CP 31290, Chihuahua, Chihuahua, México. Tel (14) 10-77-55; Fax (14) 15-04-86.
Texas Center for Policy Studies: PO Box 2618, Austin, Texas, 78768. Tel
(512) 474-0811; Fax (512) 474-0811; E-Mail: email@example.com.
National Citizens Alliance has a Web page with information about the practice of burning hazardous wastes in cement kilns and the opposition it has generated at:
Downwinders at Risk also has a Web page with similar information about the practice in Texas at: