While many U.S. businesses won't be happy over the increased cost, it's hard to argue with the new standards for exposure to hazardous materials adopted last week by the federal government.

The new rules, which set limits for worker exposure and also regulate 164 additional substances for the first time, are the first large-scale changes in such standards in nearly 20 years. That's a long time, especially since hazardous new materials are constantly being introduced into industrial use.The federal Occupational Safety and Health Administration has been under fire because of the lack of action in dealing with hazardous substances in the workplace. In the previous 17 years, only 24 materials were added to the rules limiting exposure.

Few can argue with the scope of the new changes. The OSHA rules, besides placing 164 substances under exposure rules for the first time, also reduce the exposure limits for 212 other materials, and let stand limits on 52 substances. Limits on another 169 materials not covered in the study also will remain.

Included are such things as carbon monoxide, hydrogen cyanide, and complex chemicals such as perchlorothylene. Also included for the first time are common materials like wood dust and grain dust.

The impact will be widespread. Some 21 million Americans are considered to be exposed at work to substances on the list. More than 4.5 million currently are exposed to hazardous materials at rates above the new limits.

All the new exposure limits will take effect March 1 and employers must be in compliance by Sept. 1. The cost of meeting the new standards will vary, of course, from business to business. But OSHA estimates it to be about $150 per worker a year, for a total of around $700 million a year.

However, the expanded rules can be expected to save money by reducing work-related cases of cancer, liver, and kidney ailments by 55,000 cases a year and saving 500,000 lost workdays each year. Such savings should more than pay for the added expense of making the workplace safer.

In the long run, limiting exposure to hazardous materials is an excellent investment for workers and employers alike.