The fundraiser puts volunteers in an unshaded car park all afternoon. Can I ask for a different plan?

The organiser sent the roster with my name beside the car-park table from noon until four. The table has no cover. When I asked about breaks, she said there would be bottled water under it.

The event is being planned for hot weather. I offered to volunteer before I knew the location and length of the shift. I want to help, but a box of drinks does not answer where someone can cool down or who takes over the table.

[CDC heat guidance includes staying cool, using shade, taking breaks and drinking fluids](https://www.cdc.gov/heat-health/about/index.html). I am asking about the plan before anybody becomes unwell, rather than trying to negotiate a break while a queue is waiting.

The organiser is short of people and says changing the shift now leaves the table uncovered. What would a concrete offer look like: a shorter slot, another task, or accepting the slot only if cover and breaks are arranged?