Regard (v.) is to consider or to have an opinion about something:
Picasso is regarded as one of the greatest artists in history.
I don't regard this as a problem; I regard it as an opportunity.
Regards (n.) is a greeting:
Please give my regards to your parents when you see them.
Some people end their letters/emails with the expression Regards, or With best regards,
The phrases regarding and in/with regard to mean "related to / concerning the following topic":
Have you read the report regarding the economic crisis?
Before finalizing the contract, there are a few points I'd like to clarify with regard to the deadlines.
These phrases are more formal, and in everyday spoken English we'd say "about" instead: "Have you read the report about the economic crisis?"
Regardless (adv.) means one thing is not affected by something else:
A champion keeps going, regardless of the difficulties.
The mayor approved the new law regardless of the opposition from the public.
I know we don't have all the information, but we still need to make a decision, regardless.
As you can see from the examples, the action (keep going / approving the law / making a decision) is not affected by the other situation (the difficulties / the opposition / not having all the information).
Don't use the word "irregardless" - it doesn't exist; it is a common error in English.
Puncture cooking pouches and foods that have tight skins to release steam as they cook. Never use a brown paper bag for popping popcorn. It can catch fire. These product emission limits are defined for the purpose of compliance testing, not specifically exposure protection. The International Commission on Non Ionizing Radiation Protection (ICNIRP) has published guidelines on exposure limits for the whole EMF part of the spectrum. Exposure guidelines in the microwave range are set at a level that prevents any known adverse health effect. Exposure limits for workers and for the general public are set well below levels where any hazardous heating occurs from microwave exposure.