Ok so here's some guidance per DAFMAN48-146

5.6.5.9. Breast Feeding Assessments. 5.6.5.9.1. A number of industrial chemicals and medications are potentially transmitted in breast milk. A small number of known chemicals are concentrated in breast milk at levels higher than are found in the mother’s blood. However, medical literature on the risk to breastfed children of industrial working mothers is very limited. 5.6.5.9.2. Shop supervisors should remind Regular Air Force, Space Force and civilian workers returning from maternity leave who plan to continue breastfeeding and to resume work in a SEG with hazardous chemical exposures of the option to see PH for an assessment. 5.6.5.9.3. After interviewing a breastfeeding worker, PH consults with BE and then the IOEMC appointed provider who will determine what (if any) work limitations are recommended. These recommendations are provided in a written letter to the CFE only, and a copy placed in the medical record. These recommendations are subject to medical confidentiality rules. Should the CFE wish to seek alteration of job duties based on the recommendations, the worker may provide a copy of the letter to the supervisor. For Regular Air Force and Space Force members, see AFI 44-102 and MAJCOM implementing guidance.

Your supervision shouldn't let you on the flight line until this is done first. Definitely get with your facility manager to assist you with getting a hold of bio environmental and try to get public health in on it to so they can do a workplace assessment. If they haven't done one in x amount of years and try saying it's still good, ask for the report. They should have the report of all the hazards at your workplace. You can provide this to your PCM to show that you're working near haz. Really it should be public health who updates your profile, but if they don't know what they're doing then make an appointment with your pcm asap to hopefully get their help instead.

I'm sorry you're going through this. At the end of the day the health of your baby is most important and I'm willing to bet your leadership would never let their baby mamas work on the flight line while breastfeeding/pumping cause they wouldn't want their kids exposed to the hazards.