It’s hard to find an herbicide like glyphosate. It’s cheap, highly effective, and is generally regarded as one of the safest and most environmentally benign herbicides ever discovered. But a report last year that glyphosate could cause cancer has thrown its future into jeopardy. Now the European Union faces a 30 June deadline to reapprove its use, or glyphosate will not be allowed for sale. Here’s a quick explanation of the issues.