Better barbecues and lightweight litter.

I saw warnings on bags of charcoal that said carcinogens are released when the briquettes are burned. Is it harmful to breathe in the smoke from a charcoal grill? Joe Sliwa, via e-mail

Barbecue grills can be problematic for two reasons. First, both charcoal and wood burn "dirty," producing not only hydrocarbons but also tiny soot particles that pollute the air and can aggravate heart and lung problems. Second, the grilling of meat can form two kinds of potentially carcinogenic compounds: polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs). According to the American Cancer Society, PAHs form when fat from meat drips onto the charcoal. They then rise with the smoke and can get deposited on the food. They can also form directly on the food as it is charred. The hotter the temperature and the longer the meat cooks, the more HCAs are formed. HCAs can also form on broiled and pan-fried beef, pork, fowl and fish. In fact, National Cancer Institute researchers have identified 17 different HCAs that result from cooking "muscle meats" and that may pose human cancer risks. Studies have also shown increased risk of colorectal, pancreatic and breast cancers associated with high intakes of well done, fried or barbequed meats.

According to the Texas Commission on Environmental Air Quality, Texans who say that they "live and breathe barbecue" may be doing just that to the detriment of their health. A 2003 study by scientists from Rice University found that microscopic bits of polyunsaturated fatty acids released into the atmosphere from cooking meat on backyard barbecues are one factor in Houston's serious air pollution.

Consumers can avoid exposure to charcoal's harmful additives by sticking with natural charcoal brands. Noram de Mexico's Sierra Madre 100 percent oak hardwood charcoal contains none of the coal, oil, limestone, starch, sawdust or petroleum in some mainstream products and is certified by the Rainforest Alliance's SmartWood program as sustainably harvested. The product is available at select Sam's Clubs across the U.S. Other manufacturers of all natural charcoal include Greenlink and Lazzari.

Which kinds of cat litters are kinder to the environment: traditional clay litters (so-called clumping litters) or other varieties? What about some of the new alternatives, such as those made out of wheat and corn?--Stef Gandolfi, Oakland, CA

Clay-based clumping cat litters pile up in landfills, producing chemicals that can potentially harm human health. According to the International Agency for Research on Cancer, clay litters also produce dusts that contain silicon particles, which are known human carcinogens. And the clay used for litter is obtained through strip-mining, which adversely affects surrounding soil, water and air.

Some pet owners have reported respiratory and other health problems in their cats due to both the inhalation and ingestion of dumping clay litters. Once inside the lungs or digestive tracts, the litter can expand and cause irritation and blockages. In the lungs, this can lead to infection and, in the intestines, dehydration.

There are a number of environmentally friendly alternatives. Recycled newspaper litter is biodegradable, flushable, burnable and 99 percent dust-flee. It also won't get tracked around the house.

Fibre Cycle sells paper-based cat litter that's purported to be highly absorbent, biodegradable, long lasting, lightweight and virtually dust-free. Plant-based litters are made from materials such as corn, corncobs, cornhusks, wheat by-products, wheat grass and beet pulp. According to Worldwise, a leading manufacturer of green pet products, ground corncobs are a good choice because they are biodegradable, have no odor, are very absorbent and don't produce the same kind or volume of dust as clay litters.

Litters made from pine and cedar sawdust use biodegradable scrap materials and eliminate odor naturally. Feline Pine, from Nature's Earth Products, is a wood litter that has been heated and pressurized to remove any harmful wood oils. When ready for changing, the biodegradable litter can be emptied into the backyard compost or mulching pile. One caution about pine, though: Some cats have a sensitivity to it and might shun the litter box altogether.

CONTACTS: Fibre Cycle, (011)61-7-3278-1222, www. fibrecycle.com.au; Feline Pine, (800)749-PINE, www.nature searth.com; Worldwise, [phone], www.worldwise.com/index.html.

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