Chemistry is vital for improving and sustaining the quality of human life, and the chemical process industries continue expanding to meet society’s demands, producing over a million new chemicals a year worldwide. The US chemical industry alone employs over a million workers and is the largest segment of US manufacturing. The four main areas within chemistry are organic, inorganic, analytical and physical.

Organic chemistry studies carbon compounds and how to modify and combine them to synthesize new substances. Synthetics include dyes, perfumes, refrigerants used in airconditioners and plastics such as Nylon, Plexiglass and Teflon—a polymer extensively used since the 1960s as a non-stick coating for pans. Compounds are also synthesized and screened for use as drugs or agricultural chemicals.

Inorganic chemistry treats all compounds, except for hydrocarbons and their derivatives. Advances in inorganic chemistry have yielded composite materials for constructing anything from better tennis rackets to more durable airplane wings.

Semiconductors and high-temperature superconductors have also been produced, making possible faster computers and high-speed trains.

Analytical chemistry is concerned with determining the composition of substances.

Advances since the 1950s involve increasingly sophisticated instrumentation and techniques, including ultra-centrifuges, mass spectrometers and high-resolution chromatography. X-ray crystallography has also made it possible to analyze the structures of vitamin B12, DNA and hemoglobin. Many techniques are employed to detect environmental pollutants and food contaminants.

Physical chemistry employs the instruments and methods of analytical chemistry to develop theories of chemical phenomena. Chemical thermodynamics measures variables like melting and boiling points, chemical kinetics studies reaction rates and electrochemistry examines chemical effects due to electric currents. Such information has facilitated research in and development of electronic components, alternatives for harmful chemicals and more.

Chemistry has increasingly fractured into various specializations. To mention a few: agricultural and food chemistry produce preservatives and flavorings, as well as fertilizers, pesticides and herbicides like 2,4-D, which led to rapid rises in crop yields after the Second World War. Pharmaceutical chemistry creates medicines and other drugs to treat diseases and extend and improve the quality of life. These include the antibiotics penicillin, tetracycline and aureomycin, as well as synthesis of steroids like progesterone, used for contraception, and hormones like insulin used in treating diabetes. Petrochemistry generates petroleum-based products such as gasoline, oil, waxes and plastics, as well as the raw material for most synthetic fibers.

The need to assess the benefits of chemicals versus their adverse consequences has always existed but been largely ignored by chemical manufacturers until the 1960s, creating the impression of an industry unconcerned with environmental pollution, health risks or product safety Public concerns led to the creation of the Environmental Protection Agency in 1970 and passage of various laws thereafter to protect the environment and improve workplace safety The US chemical industry has responded with programs, which include voluntary clean-ups, effluent reduction and safer disposal methods, and prioritizing employee health and safety issues, to regain public trust.