In a chemical plant, delivery operations between a tanker and storage tanks began around 9:00 a.m. The two operators in charge of the transfer operation noted that the tanker’s bottom valve was clogged by a phenol plug (toxic product, TF: 43 °C).

The decision was made to unclog the valve by injecting nitrogen. The operator closest to the tank was sprayed with liquid phenol. A 3 m² puddle of phenol formed at the base of the tank and solidified while the internal emergency plan was initiated and the emergency services alerted. Having been sprayed in the neck area, the operator was taken to the site’s infirmary, washed and then taken to the hospital. He was released in the afternoon once the contamination tests were confirmed to be negative. The puddle of phenol was cleaned up with hot water while the adjacent road was closed to avoid the risk of splashing. Once the transfer operation from the tanker was completed, it was taken to a hermetic washing booth. The contaminated rinsing water was directed to a treatment station near the site. An estimated 52 kg of phenol was lost.

The accident analysis shows that:

• the phenol had remained in the unheated tank for more than 60 hours before the transfer operation on Monday morning (over the weekend),
• the balancing fitting exhibited a sealing problem due to a faulty connection with the balancing hose connected to the vapour spaces of the tanker-tanks,
• vapour space was no longer present at the connector as the tanker contained more phenol than was authorised (29.4 t, i.e. 30.9 m³, compared to the 30 m³ authorised load as per ADR regulations) and the lorry had been parked on a slope (6%). The liquid was therefore in direct contact with the fitting,
• the operators had not been trained in the transfer line unclogging procedure which required that a supervisor be present in the event of a problem with a clogging product such as phenol,
• there were no instructions in the event the tanker’s bottom valve become blocked with a clogging product.

The operators injected nitrogen at 2 bar into the transfer line ahead of the bottom valve. The clog was removed, but the nitrogen entered the tank and pushed the product into the balancing line since no vapour space was present. The tightness defect on the fitting resulted in phenol leaking into the tanker’s upper retention system and sprayed the operator who was not wearing the recommended protection equipe. As the valve on the retention’s drain line had remained open, the leaked phenol flowed directly onto the ground.

Operator actions:

• review of the transfer procedures and, in the case of a clog, prohibit the delivery of phenol that has been stored too long in an unheated tank,
• limitation the tank’s filling volume to 25 t,
• standardisation of the diameter of the balancing hose with the tank’s connection to avoid the use of reduction fittings (a potential source of leakage),
• implementation of a matrix of roles and responsibilities during transfer operations, between the site’s operators and the external drivers (some do not speak French).