All the CSB could do is object or leave the site if they felt it was unsafe to be there.The CSB is an independent federal agency charged with investigating industrial chemical accidents. The agency does not issue fines or citations, but does make recommendations to plants, regulatory agencies such as the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), industry organizations, and labor groups. Congress designed the CSB to be non-regulatory and independent of other agencies so that its investigations might, where appropriate, review the effectiveness of regulations and regulatory enforcement.
A few more comments on the MRR incident.
Given the differing and complex views on the chemistry involved in the explosion, the CSB recommendation to evaluate the reactive hazards could prove to be an insurmountable task.
Another approach, besides not using dilute bleach, might be to vent the vessels to the atmosphere while circulating and filling the vessels to be cleaned. Each vessel should be vented separately. The vent would have to go to a scrubber or flare or both to prevent any toxic materials from being released to the atmosphere.
Further keeping the vessels liquid full (with mostly water as described on page 14 of this CSB report) would potentially to reduce the risk of any alkyl hypochlorites from forming? Certainly, not being liquid full increases the risk for trouble. Proper venting would help insure that the vessels are liquid full.
I don't agree with the use of a pressure safety valve (PSV) as recommended by the CSB on page 33. The PSV would not prevent the pressure vessel destruction from the as described explosion.