Solvent Spill to a Pond Drain at an Electroplating Shop
An electroplating shop reports monthly hazardous waste generation of 850 kg of spent chlorinated solvent and 1,200 kg of chromium-bearing rinse water. Four 200 L drums sit in a curbed, unvented room: one is unlabeled, one is dated 100 days ago, and one contains solvent plus a small amount of nitric acid from a line-cleaning batch. At 10:05 a 20 L solvent drum spill reaches a floor drain. The drain discharges to an on-site holding pond used for pH adjustment; the pond has a pH of 6.5 and a Cr(VI) concentration of 0.8 mg/L. Three workers are in the room; one complains of dizziness. The shop has no written spill procedure, and the drain has no shutoff valve. The local sewer authority requires notification within one hour for any discharge.
1. What is the immediate priority order, and what should be done with the dizzy worker and the drain?
Read the worked answer
Reasoning: Life safety comes before containment, but containment must start immediately because the drain is a direct pathway to the pond. The dizzy worker may be experiencing solvent vapor exposure, so removal to fresh air is the first clinical action.
Priority order: (1) move the worker to fresh air without sending untrained staff into the spill; call medical advice and have the person evaluated; (2) evacuate the room and eliminate ignition sources, because chlorinated solvents may have low flash points depending on the mixture and can displace oxygen; (3) protect the drain using absorbent socks, sand, or a temporary drain cover from outside the spill area; (4) notify the sewer authority within the one-hour deadline and notify EHS; (5) ventilate only with non-sparking equipment after the area is isolated; (6) absorb the free liquid with inert, solvent-rated absorbent and place it in a compatible, labeled container.
Do not flush the drain with water, which would spread the solvent and chromium, and do not use a shop vacuum unless it is rated for flammable vapors. Because there is no shutoff valve, the drain cover and diking are the only immediate controls; the lack of a valve is a corrective-action item.
2. Evaluate the accumulation room and containers; what hazards and compliance gaps do you identify?
Read the worked answer
Reasoning: The monthly totals are 850 kg of solvent plus 1,200 kg of chromium rinse water, about 2,050 kg/month. That exceeds the 1,000 kg/month large-quantity-generator threshold in the US RCRA framework, so the 90-day accumulation limit would apply to the site; verify the local jurisdiction before citing a specific limit. A drum dated 100 days old would then exceed the limit.
Container and room gaps: the unlabeled drum violates hazard communication and waste-identification requirements; the solvent-plus-nitric-acid drum is an incompatible mixture with reactivity and gas-generation potential; the room is unvented, so vapors can accumulate; the curbed room provides some containment but the drain defeats it. The drums should be inspected weekly, labeled with accumulation start dates, kept closed except when adding waste, and segregated by compatibility. The nitric-acid-containing drum should be evaluated by a chemist before any movement. The room needs ventilation, secondary containment, and a drain shutoff or sealed drain. The spill kit and written procedure are missing.
3. What corrective actions and notifications are needed after the spill?
Read the worked answer
Reasoning: The release has already reached a drainage pathway, so notification and environmental assessment are not optional. Corrective actions must address both the spill and the conditions that made it worse.
Notifications: notify the sewer authority within one hour as required; notify the environmental regulator if the release meets local reportable-quantity criteria; inform the holding-pond operator and downstream users; notify the waste contractor and insurer. Document the time, volume, pathway, and actions.
Corrective actions: install a normally closed drain valve or seal the drain; provide a written spill procedure and train workers; add secondary containment and ventilation; label all containers and start-date them; segregate acid from solvent; reduce inventory; inspect weekly; determine waste codes and manifest the spilled material and absorbents. Sample the pond for solvent and Cr(VI), verify treatment capacity, and do not resume plating until the source is controlled. Investigate why nitric acid entered the solvent drum and update the line-cleaning procedure. If the pond discharge exceeds permit limits, follow the permit's upset provisions.