The European Parliament has approved a landmark new law on Registration, Evaluation and Authorisation of Chemicals, known as REACH.
The legislation is designed to make companies prove that substances in everyday products such as cars, computers or paint are safe.
The properties of roughly 30,000 chemicals produced or imported in the European Union would have to be registered with a central agency.
Those of highest concern, such as carcinogens, would require testing and authorisation before use.
MEPs voted 407-155 in favour of the legislation, with 41 abstentions. The rules must still be agreed by EU member states and may come back to parliament before they can become a law.
MEPs also supported a measure that would force firms to substitute hazardous chemicals for safe ones when alternatives are available.
Germany, Europe's largest chemicals producer with giants like BASF and Bayer, successfully delayed a decision by member states scheduled for later this month, but Britain, which holds the EU presidency, wants a deal this year.
But greens and consumer groups have voiced disappointment and warned that the new rules leave huge risks to the environment and human health.
Since 1981, new chemicals used within the EU have been tested for their safety.
However, reports say 90% of the substances used were developed before that date.