I was told that backfeeding my electric panel through my dryer circuit with a generator could burn the house down because it has no neutral wire. Why is there no neutral wire and why wouldn't it be just as unsafe when using the dryer circuit normally. Is there a way to make it safe?

It is extremely unsafe to do this. The reason is NOT what you wrote. In fact who ever told you that has no clue. A dryer does have a neutral. Older 3-wire dryer circuits had no ground.

DO NOT even suggest ILLEGALLY backfeeding your service through a dryer receptacle.

We have had several threads on this lately.
Here:
https://www.askmehelpdesk.com/electrical-lighting/backfeeding-your-house-panel-257455.html
https://www.askmehelpdesk.com/electrical-lighting/temporary-generator-wiring-257368.html
https://www.askmehelpdesk.com/electrical-lighting/grounding-our-generator-257347.html
https://www.askmehelpdesk.com/electrical-lighting/grounding-generator-256984.html

Because the guy working on the supposedly dead utility lines, turns your 240/120 V into 9000 volts and that a bit lethal. A transformer doesn't care where the input is. Thus in one case 9000V becomes 240/120 and in the other case 240/120 becomes 9000 V.

Bet if you put 9000 V on the power line, the utility company will find you and prosecute and likely turn off your electricity. If the guy ends up dead, hope your insurance is paid up.

Interlocks and/or transfer switches are mandatory to protect the utility worker's family from collecting on your homeowner's policy and you to continue to be provided with electricity.

Pine, besides what KISS has already stated, the details are in those four threads I linked to.

Well pine, I make it a strong point to never reply to e-mails that I get from message board contacts. That is the reason for the link in my sig line. In this case I'll make an exception. Considering you chose not to receive e-mails or PM's I'll post it here.

Your "engineer" friend steered you wrong.

All I can say is check this web site. I think you got some erroneous information.

FPL: Using Portable Generators Safely (http://www.fpl.com/storm/generator_safety.shtml?WT.ad=HMRB01)