Safety, Environmental, and Contamination Control
Barbara Kanegsberg and Ed Kanegsberg, March 2004
Goals of the worker safety, environmental regulatory management, and contamination
control groups are too often considered to be unrelated, if not conflicting.
A more positive approach would be to treat the groups as parts of a collaborative
triad. For example, equipment design and process controls can have a mutually
beneficial impact on all three programs. In addition, similar techniques are
sometimes used to monitor safety, environmental, and product contamination.
Since monitoring programs can be costly in terms of manpower, production resources,
and testing budget, consolidation of effort or at least comparison of trends
and findings can have economic benefits.
Enclosed processes, minimizing worker exposure
Efforts to automate and/or contain chemicals are sometimes impelled by
regulatory constraints. Such changes are often resisted because they
are typically accompanied
by high initial costs in terms of capital equipment and engineering time.
Once the project is complete, the process is often improved. No matter
what part
of the triad spearheads the change, it is productive to have all three groups
work together. For example, a process involving cleaning with perchloroethylene
in a vapor degreaser was changed to one using automated, enclosed equipment.
Environmental regulatory requirements were the inspiration for the change.
However, those involved in worker safety, environmental compliance, and product
performance worked together beginning with the stages of brainstorming, equipment
and chemical evaluation, through selection, and process implementation. The
result was not only sharply reduced solvent emissions and very low worker
exposure but also superior process consistency and improved performance.1
Process Monitoring
Aniline-based curing agents are used in the manufacture of high performance
epoxies and polyurethanes. Methylene dianiline (MDA) is representative
of this class of curing compounds. MDA has an exceedingly low vapor pressure;
airborne
contamination is not the issue. The product Q.A. people are interested
in
a surface free of contamination so that the next process can be conducted.
Residual
MDA on the surface might interact with organic coatings, altering the color
or impacting adhesion.
Occupational safety people monitor MDA because it is a regulated carcinogen
with a TLV2 of 0.01 ppm.3 It is rapidly adsorbed through the skin and
may be adsorbed through gloves. The occupational safety people collect
information;
the Q.A. people collect information. Both groups are concerned about
surface contamination and would benefit by sharing data.
Monitoring of strontium chromate paints offer another example of possible
confluence, with emphasis on airborne contamination. Strontium chromate-based
paints are
used in corrosion protection for high performance aircraft. The TLV
is 0.0005 mg/m3 (four times lower than beryllium). Product quality
personnel
are concerned
that the paint is applied specifically. Product safety personnel are
concerned with airborne contamination either during application or
by sanding during
removal. Because the allowable employee exposure level is so very low,
monitoring by industrial hygienists can provide a valuable tool in
process control.
The surface cleanliness people should provide information to the occupational
health
people as to what is on the surface and as to what processes are intended.
Conclusions
It is not realistic to expect that a single monitoring program could
be used for all three parts of the triad. The goals of monitoring
programs for worker
safety, environmental compliance, and product contamination minimization
are quite different. For example, the OSHA standard for nuisance
particulates is
10 mg/m3; tolerable levels for surface contamination may be orders
of magnitude
lower. At the same time, increased coordination in tracking of monitoring
trends among the worker safety, environmental compliance, and product
performance might be expected to be productive for all concerned.
You want to keep the process under control for worker safety, environmental
quality, and product quality. Therefore, any trend away from the
norm of any contaminant tracked for safety, environmental, or product
quality
issues
could
signal other impending issues. The data could profitably be shared
among the three disciplines.
References:
1 Dowell et al. Presentation, International Thermal Spray Association,
Las Vegas, NV (October, 2003).
2 Registered trademark, American Conference of Governmental Industrial
Hygienists.
3 http://www.osha.gov/pls/shaweb/owadisp.show_
document?p_table=STA NDARDS&p_id=10081, OSHA Standard for Methylene Dianiline,1910.1050,
particularly Appendix A.
Barbara Kanegsberg and Ed Kanegsberg are independent consultants in critical cleaning, precision cleaning, surface preparation, and contamination control. They are the editors of “Handbook for Critical Cleaning,” CRC Press. Contact them at BFK Solutions LLC., 310-459-3614; info@bfksolutions.com; www.bfksolutions.com.
