34. California

California deserves its own section because four instruments apply there side by side, and because the groundwater case that made chromium(VI) publicly known, Hinkley, is described in Section 24.

Proposition 65: the warning duty and who enforces it

The Safe Drinking Water and Toxic Enforcement Act of 1986 provides in section 25249.6 of the Health and Safety Code: “No person in the course of doing business shall knowingly and intentionally expose any individual to a chemical known to the state to cause cancer or reproductive toxicity without first giving clear and reasonable warning to such individual, except as provided in Section 25249.10.” [162]

Hexavalent chromium appears twice on the list maintained by the Office of Environmental Health Hazard Assessment, which is published in section 27001 of Title 27 of the California Code of Regulations. The entry “Chromium (hexavalent compounds)” carries the toxicity type cancer with the listing date 27 February 1987, and a second entry of the same name carries developmental toxicity, female reproductive toxicity and male reproductive toxicity with the listing date 19 December 2008. Neither entry gives a CAS number, because the listing covers several substances. [163]

The levels below which no warning is required are set in regulation. Section 25705(b)(1) of Title 27 gives the No Significant Risk Level for chromium (hexavalent compounds) as 0.001 micrograms per day by inhalation, and section 25805(b) gives the Maximum Allowable Dose Level as 8.2 micrograms per day by the oral route. The inhalation figure is the lowest regulatory quantity that appears anywhere in this analysis. [164]

Enforcement does not depend on an authority taking the matter up. Section 25249.7(b)(1) provides a civil penalty “not to exceed two thousand five hundred dollars ($2,500) per day for each violation”, and section 25249.7(d) permits actions “by a person in the public interest” where notice has been given more than sixty days earlier to the Attorney General and to the local prosecutor and to the alleged violator, and where a certificate of merit executed by the noticing party or its attorney accompanies the notice, confirming consultation with one or more persons with relevant experience and the belief that there is “a reasonable and meritorious case for the private action”. [162]

For the case dealt with here the significance of this instrument lies in what it does not require. It does not ask where the compound came from, it does not ask whether anyone placed it on the market, and it does not ask for a limit value in air to have been exceeded. It attaches to the knowing and intentional exposure of an individual, with a reference quantity of 0.001 micrograms per day by inhalation, and it can be enforced by any person in the public interest. [162, 164]

Cal/OSHA: the state standard and a reporting duty

California operates one of the state plans approved by the federal Occupational Safety and Health Administration. There are at present 22 such plans covering both the private sector and state and local government workers, and seven covering state and local government workers only. [165]

The Californian chromium(VI) standard is section 5206 of Title 8 of the California Code of Regulations, headed “Chromium (VI)” and placed in Article 110, Regulated Carcinogens. Its permissible exposure limit and its action level are worded as in the federal standard. It adds, in subsection (o), a reporting requirement: “Reporting requirements. See Section 5203.” Section 5203 is headed “Carcinogen Report of Use Requirements” and provides in subsection (a): “All employers who use a regulated carcinogen shall report that use in writing to the Chief as required by this section.” [166, 167]

That duty has no counterpart in the federal standard. It is directed at the use of a regulated carcinogen, and it turns on the same question as the European use concept in Section 25: whether the handling, storing and reinstalling of a chromate-bearing component is a use of the substance.

Drinking water: 10 micrograms per litre, with a history

Since 1 October 2024 California has had a maximum contaminant level for hexavalent chromium in drinking water. Table 64431-A in section 64431 of Title 22 of the California Code of Regulations gives it as “Chromium (hexavalent) 0.010”, that is 10 micrograms per litre. The State Water Resources Control Board adopted the regulation by Resolution 2024-0015 on 17 April 2024; the Office of Administrative Law approved it on 24 July 2024, and the effective date was 1 October 2024. Compliance dates are staggered by the size of the system, beginning on 1 October 2026 for systems with 10,000 or more service connections. Before that date hexavalent chromium was covered by the total chromium limit of 50 micrograms per litre, which remains in force. [168]

The history belongs to the picture. A limit value of the same figure had already been adopted in April 2014, approved on 28 May 2014 and in force from 1 July 2014. On 31 May 2017 the Superior Court of Sacramento County invalidated it on the ground that the regulation had failed properly to consider the economic feasibility of compliance. By its own account the court made no finding on whether the limit value protected public health, and reached no conclusion on whether it was too low or too high. The Water Board then deleted the regulation text by Resolution 2017-0045 of 1 August 2017, and the state had no separate limit value for hexavalent chromium for seven years. [169]

Two observations follow, and both bear on the subject of this analysis. A figure of 10 micrograms per litre in drinking water, next to a No Significant Risk Level of 0.001 micrograms per day by inhalation, next to a workplace limit value of 5 micrograms per cubic metre, shows how far the regulatory quantities for one and the same substance lie apart once the pathway changes. And the ground on which the first limit value fell was not the toxicology but the cost of compliance.