Top Toxic Targets

Many household products, including cleaners, garden pesticides, and paint strippers, contain toxic ingredients that can adversely affect human health and the environment. But when you want to change to safer products, where do you start?

It's easy to get overwhelmed by the number of toxic chemicals that you might be exposed to. But we know that eliminating exposure to the carcinogens in tobacco smoke reduced the incidence of lung cancer. We know that eliminating the lead from gasoline reduced the incidence of lead-associated developmental problems in children. If we can focus on those areas where we can make a change, it can break down a huge task into some logical steps for action.

Over the last few decades, science has done a lot to identify certain toxic classes of chemicals and to group them into lists. Three of the most important, from a human health and environmental standpoint, are:

• Carcinogens
• Reproductive toxins
• Endocrine disrupters

In plain language, carcinogens are substances that can cause cancer. They do it by altering or damaging the cell's DNA - the basic coding system of cells - or by impairing the body's natural defences that protect against the formation of cancerous cells.

Since the 1960s, various national and international agencies have compiled studies of carcinogenic substances. Most of the studies are based on experimental data with animals, but studies based on occupational exposures in the workplace are also adding to our knowledge. The lists of potential carcinogens have been compiled based on that experimental data. The lists that LEAS uses to establish whether a substance is carcinogenic are:

• International Agency for Research on Cancer (IARC)



• U.S. National Toxicology Program (NTP)



• Office of Environmental Health Hazards Assessment (OEHHA), a California agency set up under a 1986 initiative called Proposition 65. The agency maintains lists of carcinogens and reproductive toxins.



• U.S. Environmental Protection Agency Office of Pesticide Programs (EPA)

The standard that is used to determine whether a chemical should be listed as carcinogenic is very rigorous - if a chemical appears on a list of carcinogens, then that cancer-causing effect has been demonstrated in many studies.

In the occupational field, a number of unions have waged campaigns to reduce workers' exposure to carcinogens such as asbestos and some industrial solvents. In many cases, they have succeeded in eliminating carcinogens from the workplace.

Still, a number of carcinogens show up in common household products and pesticide products where they can potentially cause harm. Identifying those products and avoiding them is a positive step in primary cancer prevention.

Chemical substances can easily affect reproduction and fetal development, especially if that interference comes at a critical stage.

Reproductive toxins can have a number of adverse effects, from damaged sperm in men to infertility in women, and early puberty. A sub-category of reproductive toxins includes a number of developmental toxins that can potentially affect babies during fetal development or children during the early stages of growth.

California's Office of Environmental Health Hazard Assessment maintains a list of substances "known to the state of California to cause reproductive toxicity," including toluene and number of household pesticide ingredients. Environment Canada also includes suspected reproductive toxins such as 2-butoxyethanol among the chemicals it has listed as CEPA-toxic, according to the Canadian Environmental Protection Act (CEPA).

Nearly a decade ago, U.S. scientists Theo Colburn and John Peterson Myers, together with science journalist Dianne Dumanoski, published Our Stolen Future, a book that brought to popular attention the damage caused by endocrine-disrupting chemicals, or EDCs. EDCs are chemically similar to the hormones naturally produced by humans and others in the animal world. Because of that, they tend to "disrupt" the actions of those hormones. Sometimes they block the natural hormones and sometimes they mimic or enhance their effect, with unpredictable results.

The greatest impact of EDCs is in the environment where they can cause a range of adverse effects. Many of those are in the area of reproduction, posing a potential risk to survival for some species.

The European Commission and the U.S. Environmental Protection Agency have both compiled lists of endocrine disrupting chemicals, based on research data. Then European Union uses its list as a basis for regulating the use of chemicals in products. For example, ethoxylated nonyl phenols, which are still used in some cleaning products in Canada, are banned from use in cleaning products in the EU.