Deepening knowledge of the differing ways that chemicals can turn normal cells into runaway masses of malignancy may add new complexity to the effort to regulate cancer-causing substances, many experts say.

Proposition 65 regulates substances listed by California as causing cancer or birth defects or other reproductive harm in two ways.

EPA scientists are dedicated to developing ways to help produce safer chemicals and regulate harmful substances.

Many countries regulate such substances as therapeutic goods or pharmaceuticals or by some other category, without requiring them to be shown to be medically useful.

In addition, he said, laws regulating toxic substances should be enforced, which, he contended, was not being done by President Reagan's Administration.

They have also found growth regulating substances, which could accelerate the growth of crops while inhibiting the roots.

These laws regulated public drinking water systems, toxic substances, pesticides, and ocean dumping; and protected wildlife, wilderness, and wild and scenic rivers.

It is important to regulate substances which have a proven adverse effect on human health.

The EPA regulates substances with pesticide characteristics, looking at potential threats to human health or the environment.

These tissues have high rates of cell division and either concentrate or produce required growth regulating substances including auxins and cytokinins.