The chemicals that are used today are both good and bad results, but may be more. Therefore, we will use the chemicals to be used, or use, in some cases, the required.
Chemicals used today have both good and bad, but it might be costly. Therefore, we use chemicals should be kept to a minimum or in some cases, required.
The chemicals used in nowadays there are both advantages and disadvantages, but there may be adverse effects. Therefore, we will use chemicals should use a minimal or choose to use in some cases required.