Current company joined a COOP and being asked to do more work

My current company joined a coop, while I was initially told I would have nothing to do for the COOP, now they want me to create specs and nutritionals for the COOP, can I refuse? Or could I ask for additional compensation?

What is your job title? 

Most jobs have an 'as assigned' aspect to them, so yes, you can say no...but there may be repercussions.  Depending on the size of your company and your position, it may actually be part of your job.

IS there a signed contract.........what does it say you are responsible for?

this happens all the time-------------I wouldn't refuse, but would absolutely explain why my compensation needed to change

When taking on new roles - this can be used as leverage for when your review happens. Helps with getting the maximum allowed raise.

Like others have said - many of us have had new roles/jobs assigned to us. Could you use this as a way to get more hours/overtime if you are hourly?

You can choose to do anything you wish....that's the beauty of free will.  However, there are consequences, good or bad.  Others have already given good advice.

You need to look at your employment contract - might  contain something along the lines of "...and any other task the company deems...  which means they can load you up with all sorts of things.

I actually had an interesting situation years ago with a company that changed my status from independent contractor (this was acceptable to me at the time) to full time SQF/3rd Party Audit Manager, gave me a salary of about $150,000 and benefits - everything was nicely laid out in an employment contract (people wonder why I hate being an employee) and it clearly showed the ins and outs of doing my job as a cross-country auditor - pretty much 1 a day and all the admin/travel that comes with it.

Everything was great for about 6 months and then they wanted me to travel on Sunday instead of Monday and do try to fly home late Friday night or early Saturday was the message I got - then they started loading extra audits in on a daily basis.

Finally I found myself stressing, not keeping up and then they fired me.  I had an attorney review my employment contract prior to the firing... yes, indeed I sued the company big time and won.

So fine tooth comb you employment contract.