INGREDIENTS The main ingredient of fireworks is black powder, a ground-up mixture of potassium nitrate, sulfur and charcoal. It is said to have been invented by the Chinese around 1,000 A.D. COLORS Six basic colors are produced by the addition of various chemicals. WHITE Magnesium or aluminum. YELLOW Sodium salts. ORANGE OR AMBER Charcoal or iron. RED Strontium salts. BLUE Copper salts in the presence of a volatile chlorine donor. To date no one has produced a deep, bright blue. GREEN Barium nitrate. SAFETY TIPS :: Read and follow directions. :: Have an adult present. :: Buy fireworks from a reliable dealer. :: Ignite outdoors. :: Have water handy. :: Never experiment or attempt to make your own fireworks. :: Light one at a time. :: If it malfunctions, don't try to relight it. :: Keep at a safe distance. :: Never give to small children. :: Store in a cool, dry place. :: Dispose of properly. :: Never throw fireworks at another person. :: Never carry fireworks in your pocket. :: Never shoot them in metal or glass containers. :: Avoid fireworks that leak powder or have a loose fuse. :: Avoid unmarked fireworks. They are probably illegal and dangerous. :: Avoid fireworks that are very old or appear to have been wet and then dried.

FIREWORKS IN THE U.S. is about a $100 million- a-year business, with imports accounting for about two-thirds of the total. China, the country where pyrotechnics originated, has reestablished itself firmly as the dominant producer in the world. There are about 40 U.S. firms with about 1,000 employes currently making fireworks. REGULATIONS DISTRICT

Sparklers, fountains, cones, spinning wheels, helicopters and some novelty items such as snakes or snap-and-pops are legal. But firecrackers, skyrockets and sparklers that shoot more than 20 inches are prohibited. MARYLAND

All fireworks, including sparklers, are illegal in Montgomery and Prince George's counties and in Baltimore. In all other counties, only sparklers that have gold-colored labels are legal. VIRGINIA

The laws vary from county to county: Prince William, Fauquier, Stafford, Loudoun, Fairfax and Arlington counties and the City of Fairfax ban fireworks that shoot a distance of more than 12 feet or that shoot projectiles. Alexandria bans the use or sale of any type of fireworks. INJURIES FROM FIREWORKS IN THE U.S. Estimate from U.S. Consumer Product Safety Comm. 1984 9,900 1985 10,300 1986 12,600 FIREWORKS INJURIES IN 1986 MARYLAND State total -- 20 Anne Arundel -- 0 Calvert -- 2 Charles -- 1 Frederick -- 1 Howard County -- 0 Montgomery -- 9 Prince George's -- 5 injuries

and 2 deaths St. Mary's -- 1 DISTRICT -- 11 VIRGINIA (state total N/A) Alexandria -- 0 Arlington -- 0 Fairfax -- 6 Fauquier -- 2 Loudoun -- 4 Prince William -- 3 Stafford -- N/A ILLEGAL FIREWORKS Cherry bombs, Silver Salutes, M-80's and M-100's have been banned by Federal law since 1966 because of the large amount of explosive they contain. Most serious injuries result from illegal, explosive fireworks. In the area, rockets and small firecrackers are also illegal. Check with local authorities SOURCES: American Pyrotechnics Association; jurisdictions involved.