Aerospace and defense: the hazards come from the surface treatments

Aerospace facilities have their own mix of air and noise hazards, and most of them come from the surface treatments, not from the metal.

• Hexavalent chromium from chromate conversion coatings and chromate primers
• Isocyanates from two-part polyurethane topcoats
• Solvents from degreasing and surface preparation
• Noise from riveting, grinding and test cells
• Composite work, with dust and resin systems that fall outside the standard list of substances laboratories analyze for

Hexavalent chromium and isocyanates are among the most difficult substances to sample correctly, and the choice of filter determines whether the result means anything.

Hexavalent chromium in chromate primers

Spraying chromate primer is a well-documented high-exposure task, and OSHA sets tight limits for it. The permissible exposure limit (PEL) is 5 micrograms per cubic meter of air (µg/m³), and the action level is 2.5 µg/m³.

Those are very small quantities. The smallest amount the lab can measure sits close to the levels we sample for, so field technique shows up directly in the result.

The right filter depends on the operation. OSHA's current analytical method (OSHA ID-215 v.2, revised April 2006) calls for a 5.0 micrometer (µm) PVC filter for painting and welding. For chromium plating it calls for a quartz fiber filter coated with sodium hydroxide (NaOH), so a shop that does both needs both. The version matters as well, because the bare number ID-215, without the v.2, is the withdrawn method.

→ How we sample for hexavalent chromium

Isocyanates in polyurethane topcoats

Hexamethylene diisocyanate (HDI) has no OSHA PEL at all. That does not mean you have no obligation. The obligation comes through the General Duty Clause and, where workers wear respirators, through OSHA's respiratory protection standard. The number that does the real work is the threshold limit value (TLV) published by ACGIH.

Isocyanates also have to be collected on derivatizing media, meaning a filter treated with a reagent that captures them. With a standard filter you do not get a wrong answer. You get no answer, and you find out when the lab report comes back.

Most modern industrial coatings are formulated with polyisocyanate oligomers, the larger, linked forms of isocyanate, and they contain little of the free single-unit form, called monomer. A method that captures only the monomer will report far less than workers are actually breathing.

→ How we sample for isocyanates

Adding ISO 14001 to AS9100

Aerospace suppliers already run AS9100, the aerospace quality standard, so you already have a management system along with internal audits, management review, document control and corrective action.

ISO 14001 is the international standard for environmental management systems. Adding it to an existing AS9100 system costs much less than building one from scratch. Both standards follow the same outline, called the Harmonized Structure, so their clauses overlap heavily. You run one internal audit program and hold one management review.

There is one honest limit on that. We have found no aerospace prime that publishes a requirement for its suppliers to hold ISO 14001, and what primes flow down to suppliers is mostly AS9100. The case for ISO 14001 here is therefore about running your plant and winning work, not about a contract, and we would rather you adopt it for that reason.

→ ISO 14001 consulting · The ISO 14001:2026 revision

Arizona's aerospace base

Arizona has a real cluster of aerospace and defense work, and it is our home market.

Honeywell Aerospace has been an independent public company since June 2026 (Nasdaq: HONA), with headquarters in Phoenix. Raytheon, an RTX business, has its main missile design and production site in Tucson. Boeing builds the AH-64 Apache at Falcon Field in Mesa, with nearly 5,000 people across the state.

Around those primes sits a large base of Tier-2 and Tier-3 suppliers doing machining, finishing, plating, coating and composites, and that is where most of the exposure monitoring work actually is.

What we do for aerospace plants

An air monitoring survey measures what your workers are breathing, and a noise survey measures the noise exposure of each job. We also help you build an ISO 14001 environmental management system.