Very few states regulate tattooing. It's often regulated by the municipality though. Also, a good tattoo artist self-regulates and would surpass the Maine regulations without being forced to adhere to anything.
Bmezine.com is a really good reference site for anything related to body mods (warning: some of the content is not work safe). They have a full faq file on sanitation and tattoos.
http://www.cs.uu.nl/wais/html/na-dir/bodyart/tattoo-faq/part3.htmlHere is the part of the sanitation faq on what to look for in a sanitary studio. Provided they adhere to those standards, they are safe regardless of the usually non-existent state regulation.
WHAT TO LOOK FOR IN A SANITARY SHOP ENVIRONMENT
The current popularity of tattooing and body piercing has also brought
on an increase in potentially hazardous conditions. RAB regulars have
begun posting information on unsanitary practices. For this reason, I am
posting the following guideline of what to look out for (in this
situation, "artist" refers to both tattooists and piercers):
-Lighting: The area must be well-lit so the artist can see what s/he is
doing.
-Counter and floor space should be lightly colored, preferably white so
dirt shows up easier.
-The spray bottle the artist uses on your skin should be disinfected
between customers, or some kind of protective film such as Saran Wrap
should be used.
-Disposing needles: All needles must be either discarded after EACH use
(or at least with each new customer), or autoclaved. Many body piercers
operate out of small booths and may not have spent money for an
autoclaver, in which they MUST dispose of each needle. NO EXCEPTIONS.
Reusing piercing needles is equivalent to sharing IV drugs with
strangers.
-Needles touching other things: The needles, once open from their
sanitary packages, must not be placed on unsanitized surfaces. The
piercer should NOT set the needle down on the table, or, heaven forbid,
DROP THE NEEDLE ON THE FLOOR!!! If this happens, insist they open a new
needle.
-Gloves: The artist must wash their hands prior to putting on their
gloves, preferably with an antibacterial/antiseptic solution. Once they
put their gloves on, they should not touch anything other than your
skin, the needle, and the jewelry. They should not be filling out
receipts beforehand, or answering the phone--unless these have been
wiped clean beforehand.
-Is there a sink separate from the bathroom sink?
-Does the artist use a disposable razor when shaving skin?
-The Speed Stick used as an ahesive for the tattoo pattern should not be
directly applied to the skin, but applied first to a tissue which can
then be used on the skin.
-Autoclaves should be inspected regularly.
-Sterile materials should be stored in sealed containers away from
things that could cause body fluids or ink to splash on them
-The palate that holds the ink caps should be covered with Saran Wrap
-After tattooing, the ink caps should be discarded and the ink not
reused or poured back into the bottles
Be particularly wary of "outdoor fair booths." While many are run by
caring, experienced artists, these booths allow fly-by-night operators
to make some fast money and disappear. If you don't know the artist,
spend time watching them work on others first. Are they reusing needles?
Do they use needles that have dropped on the ground?
If you see any unsanitary conditions that are particularly alarming,
post them to RAB (better yet--email me or Ardvark for the Piercing FAQ)!
If you feel uncomfortable "naming names," then withhold the specifics
for private email. It is each customer's right to guard against getting
a contamination. Worse, If you have had more than one tattoo or pierce
within several months, it will be difficult for you to prove WHICH
artist was responsible!