Toxic Tort Legal Glossary: M

Malignant Mesothelioma: A very rare form of cancer linked to asbestos exposure that occurs in the sac lining of the chest (pleural mesothelioma) or abdomen (peritoneal mesothelioma), or the lining of the heart (pericardial mesothelioma).

Manufacturers Formulation: A list of substances or component parts as described by the maker of a coating, pesticide, or other product containing chemicals or other substances.

Margin of Safety: Maximum amount of exposure producing no measurable effect in animals (or studied humans) divided by the actual amount of human exposure in a population.

Material Safety Data Sheet: Printed material concerning a hazardous chemical, or Extremely Hazardous Substance, including its physical properties, hazards to personnel, fire and explosion potential, safe handling recommendations, health effects, fire fighting techniques, reactivity, and proper disposal. These were originally established for employee safety by OSHA.

Maximum Contaminant Level: The maximum permissible level of a contaminant in water which is delivered to the free flowing outlet of the ultimate user of a public water system, except in the case of turbidity where the maximum permissible level is measured at the point of entry to the distribution system. Contaminants added to the water under circumstances controlled by the user are excluded from this definition, except those contaminants resulting from the corrosion of piping and plumbing caused by water quality.

Mercury(Hg): Also known as "quicksilver," this metal is used in the paper pulp and chemical industries, in the manufacture of thermometers, thermostats, high efficiency lighting and many other products and fungicides.  In lighting, mercury is what makes them energy efficient.  Mercury exists in three biologically important forms, elemental, inorganic and organic.  Mercury is toxic to humans.  Overexposure to mercury can affect the nervous system, kidneys and other organs.  Mercury accumulates in animals that are high in the food chain (i.e., predators).  Human exposure to mercury is largely due to eating contaminated fish.

Mesothelioma: A malignant tumor of the Mesothelium caused by exposure to asbestos fibers.

Methoxychlor: Pesticide that causes adverse health effects in domestic water supplies and is toxic to freshwater and marine aquatic life.

Micro-organisms: Bacteria, yeasts, simple fungi, algae, protozoans, and a number of other organisms that are microscopic in size. Most are beneficial but some produce disease. Others are involved in composting and sewage treatment. Milligrams/liter (mg/l): A measure of concentration used in the measurement of fluids. Mg/l is the most common way to present a concentration in water and is roughly equivalent to parts per million.

Mitigation: Measures taken to reduce adverse effects on the environment.

Mobile Source: Any non-stationary source of air pollution such as cars, trucks, motorcycles, buses, airplanes, locomotives.

Municipal Discharge: Discharge of effluent from waste water treatment plants which receive waste water from households, commercial establishments, and industries in the coastal drainage basin. Combined sewer/separate storm overflows are included in this category.

Municipal Sewage: Wastes (mostly liquid) originating from a community; may be composed of domestic waste waters and/or industrial waste waters.

Mutagenicity: The capacity of a chemical or physical agent to cause permanent alteration of the genetic material within living cells.