Yes, you need a null hypothesis ... not all papers use an alternate hypothesis. They just say that the null hypothesis failed or that it was not accepted.
Voluntary programs on employee safety reduces workplace accidents.
for the null hypothesis, but it should be the alternate hypothesis. The null should be:
The number of accidents in a work environment is not affected by voluntary programs on employee safety.
Following this, after the research and analysis, you can say that the null hypothesis is rejected rather than saying that the voluntary programs reduce (or increase) the number of accidents in a work environment.
Or you can state the alternative hypothesis
The number of accidents in a work environment is significantly affected by voluntary programs on employee safety.
Either way, good luck to you. I am going to opt out of this question as you need it completed today and I am not clear on your needs.