37. A question to American practice

The facts set out in this analysis have a long record, and much of it is American. The formation of calcium chromate and sodium chromate from a chromium source, lime or soda and oxygen was claimed as a process in a United States patent granted in 1939 (Section 7). A report prepared in 1969 for the National Air Pollution Control Administration named the chromium pathway as a research question (Section 15). An American boiler manufacturer issued a notice in April 1990 and extended it expressly to insulation materials and textiles in 1994 (Section 16). The formation at the metal-insulation interface was demonstrated by X-ray diffraction in 2015, with 160 mg of chromium(VI) per square metre of contact area after 1,000 hours and 940 mg/m² after 5,000 hours (Section 10). A Californian air quality authority had the process measured in 2021 (Section 36). The number of maintenance and overhaul occasions per year, for the industrial segments alone, is estimated in Section 32 at between 58,000 and 61,000, with millions of workshop visits on top of that.

Hexavalent chromium has been listed in California as a carcinogen since 27 February 1987, and as a developmental and reproductive toxicant since 19 December 2008, with a No Significant Risk Level of 0.001 micrograms per day by inhalation and a warning duty enforceable by any person in the public interest. The groundwater case at Hinkley is among the best known environmental cases in the country. The legal system in which all this sits has worked through asbestos over five decades.

My question is why the formation of chromates on insulated chromium-alloyed hot components has not been taken up in that system, although every element of it has been publicly documented for decades.

I do not think the answer lies in the evidence, and I do not think it lies in the instruments. Section 25 describes the mechanism, and it answers this question as well. The industrially manufactured compound has a manufacturer, a supplier, a label, a safety data sheet and trained personnel. The compound that forms in situ is encountered as a deposit on a surface. It has no manufacturer, no supplier, no label and no safety data sheet, and it therefore falls out of the category of hazardous substance and into the category of dirt. It is treated accordingly, with rags, brushes, vacuums, compressed air and spray products, by the maintenance and cleaning personnel already present. What has no product has no addressee, and what has no addressee is not taken up.

The instruments are nevertheless there. Paragraph (d)(1)(ii) of the Hazard Communication Standard places the chemical reaction products of known or reasonably anticipated uses on the side of the manufacturer of the material. The scope of 29 CFR 1910.1026 covers chromium(VI) in all forms and compounds, with no condition that anyone have named the source. Section 25249.6 of the Californian Health and Safety Code attaches to the exposure and not to the product. Section 37 of this analysis therefore does not ask for a new rule. It asks why the existing ones have not been applied to this case. [157, 153, 162]