Nice stuff all around.
Haven't seen a tanker like that before, so I looked up that chemical code; it comes back as "Nitro-o-anisidine" also know as "2-Methoxy-4-nitroaniline".
Used for non-pesticide agricultural products, ink, toner, paint, coatings, and various other colorant/coating applications.
Here's a direct copy from the US Gov's chemical info site/system:
H302 (99.53%): Harmful if swallowed [Warning Acute toxicity, oral]
H315 (19.25%): Causes skin irritation [Warning Skin corrosion/irritation]
H319 (19.25%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]
H335 (18.78%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]
H351 (59.15%): Suspected of causing cancer [Warning Carcinogenicity]
H411 (61.03%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]
Seems like some bad stuff. Cool catch, though, for sure.