Baycol: Baycol is one of several drugs known as "statins" which help lower the so-called "bad kind" of cholesterol. It does this by promoting production of high-density lipoproteins (HDL), the "good" cholesterol that lowers the artery-clogging risk of high levels of LDL. Baycol was withdrawn from the market in August of 2001. It can cause skeletal muscle damage leading to a condition called Rhabdomyolysis, which can result in kidney failure and death.

Bextra: Bextra, a pain-reliever used to treat arthritis and other painful conditions, was withdrawn from the market in April of 2005 following a study that used information from several Bextra trials proposed that the use of Bextra in high-risk cardiac patients more than doubled patient risk for heart attack and stroke.

Backflow: A reverse flow condition, created by a difference in water pressures, which causes water to flow back into the distribution pipes of a potable water supply from any source or sources other than an intended source.

Bacteria: Microscopic living organisms that can aid in pollution control by metabolizing organic matter in sewage, oil spills or other pollutants. However, bacteria in soil, water or air can also cause human, animal and plant health problems.

Best Management Practices: Structural, nonstructural and managerial techniques that are recognized to be the most effective and practical means to control non-point source pollutants yet are compatible with the productive use of the resource to which they are applied. BMPs are used in both urban and agricultural areas.

Bioaccumulants: Substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted.

Bioassay: A method used to determine the toxicity of specific chemical contaminants. A number of individuals of a sensitive species are placed in water containing specific concentrations of the contaminant for a specified period of time.

Biochemicals: Chemicals which are either naturally occurring or identical to naturally occurring substances. Examples include hormones, pheromones, and enzymes. Biochemicals function as pesticides through non-toxic, non-lethal modes of action, such as disrupting the mating pattern of insects, regulating growth, or acting as repellants. Biochemicals tend to be environmentally compatible and are thus important to Integrated Pest Management programs.

Biodegradable: The ability of a substance to be broken down physically and/or chemically by microorganisms. For example, many chemicals, food scraps, cotton, wool, and paper are bio-degradable; plastics and polyester generally are not.

Biologicals: Vaccines, cultures and other preparations made from living organisms and their products, intended for use in diagnosing, immunizing, or treating humans or animals, or in related research.

Biopsy: A procedure performed with a needle or surgical incision to remove a tissue sample to determine the presence of cancer cells through microscopic analysis.

Bioremediation: The use of living organisms (e.g., bacteria) to clean up oil spills or remove other pollutants from soil, water, and wastewater, use of organisms such as non-harmful insects to remove agricultural pests or counteract diseases of trees, plants, and garden soil.

Black water: Water that contains animal, human, or food waste.

Brine Mud: Waste material, often associated with well-drilling or mining, composed of mineral salts or other inorganic compounds.

Bronchoscopy: A thin, lighted tube inserted through the nose or mouth to examine the breathing passages at the entrance to your lungs.