zigbee as wireless network

Hello friends,
I am working on a project " wireless temperature logger ".

I need to transmit the temperature using wireless. Presently I am using zigbee module to transmit data for testing purpose.

The place where the system will be placed is a chemical plant ( hazardous area).
The system has to be enclosed in a flameproof enclosure.

Since I am new to the wireless technology. I have few doubts.

1. Is it possible to use wireless in hazardous area?
2. Is zigbee a good choice? what other options I can try ?
3. how it will afftect the range when the system will be enclosed in a flameproof enclosure?
4. what precautions I need to take for the system to work successfully?

Your help would be appreciated. Thanks in advance!!!