What can I use to seam a quartz countertop besides epoxy?
Find an adhesive that is Greenguard Gold Certified

GREENGUARD Certification  helps buyers identify interior products and materials that have low chemical emissions, improving the quality of the air in which the products are used.

GREENGUARD Gold Certification (formerly known as GREENGUARD Children &amp; Schools Certification) offers stricter certification criteria, considers safety factors to account for sensitive individuals (such as children and the elderly), and ensures that a product is acceptable for use in environments such as schools and healthcare facilities.

If there is a specific chemical that you are sensitive to you can get the data sheet for the adhesive to see if it contains that chemical.